New Delhi, India – Two of the world’s biggest militaries, Russia and India, have made their most substantive defence pact yet, allowing them to station soldiers and aircraft on each other’s territory.

The Reciprocal Exchange of Logistics Support (RELOS) bilateral agreement, which was signed last year and is now operational, facilitates the countries’ use of each other’s military bases, naval ports, and airfields during peace and wartime.

In a significant shift, India – the world’s most populous country – has allowed a foreign military to temporarily station soldiers for the first time on its soil.

This deepening of Russia-India ties, especially in the defence sector, comes amid a series of global wars that have roiled the world’s economy, in the shadow of US President Donald Trump’s unpredictable policymaking, impacting millions in New Delhi and Moscow.

So, what is in the defence agreement? How does it benefit Russia and India?

What is in the RELOS agreement?

Negotiated over the past eight years, the RELOS agreement was signed in Moscow in February last year. Russian President Vladimir Putin ratified it under federal law on December 15.

The pact has been in force since January 12, but the details were finally published by Russian officials only this week.

The RELOS agreement will remain active for five years, with provisions to extend it with mutual consent. Critically, the pact allows both countries to station 3,000 troops, five warships, and 10 military aircraft on each other’s territory.

In a statement following ratification, the Kremlin said: “The purpose of the Agreement is to define the procedure for the deployment of military formations, port calls by warships, and the use of airspace and airfield infrastructure by military aircraft of the Parties.”

The logistics support pact also sets the framework for a wide range of services, including refuelling, repairs, and supplies for warships and aircraft. In short, the agreement, analysts said, streamlines servicing of Russian military hardware that already makes up the majority of India’s inventory.

The pact now governs port access and the supply of food, water, and technical resources for naval forces. For airborne platforms, the pact includes air traffic control, navigation support, and aircraft security, as well as fuel, lubricants and maintenance services.

RELOS will also facilitate cross-training between militaries alongside Humanitarian Assistance and Disaster Relief (HADR) missions in the countries’ areas of interest.

How does RELOS benefit Russia?

Since the Cold War era, the defence sector has been the central pillar of the Russia-India bilateral relationship, with Moscow positioned as a major arms supplier to India since the 1960s.

After Russia invaded Ukraine in February 2022, India became one of the biggest buyers of its discounted crude following Western sanctions. For that, New Delhi faced the wrath of US President Trump and European leaders, who said that purchases by India were driving Putin’s war machine.

Now, the agreement gives Russia groundbreaking access to the Indian Ocean, and, in turn, New Delhi can access ports along the northern sea route from Vladivostok to Murmansk. These are critical to safeguard against global supply disruption, analysts say.

Andrey Kortunov, the academic director of the Russian International Affairs Council, a think tank in Moscow, told Al Jazeera that the RELOS agreement deepens the existing bilateral partnership.

“It gives the sides unrestricted access to the partner’s infrastructure and provides for reciprocal limited military presence on each other’s territory,” Kortunov said. “It enhances power projection and military outreach capabilities for the two sides.”

Currently, Russia does not have any military bases or other infrastructure in the Indian Ocean, noted Kortunov. “This pact helps Moscow to gain such capabilities,” he added.

Amitabh Singh, an associate professor at the Centre for Russian and Central Asian Studies in Delhi’s Jawaharlal Nehru University, told Al Jazeera: “For Moscow, RELOS is less of a wartime alliance than a sanctions-era sort of mobility pact.”

Singh added that the agreement keeps Moscow and New Delhi close amid global pressure over the Kremlin’s war on Ukraine and widens Russia’s options.

“The strategic value for Moscow is having this operational range now, where Russian ships and aircraft can stay deployed longer in the Indian Ocean region, and even nearby sea lanes,” Singh said. “From Moscow, the Indian Ocean, which has turned into a theatre of action recently, is a faraway world geographically.”

“The agreement also helps Russia signal that it still has meaningful partnerships in Asia,” he added.

How does RELOS benefit India?

Ajai Malhotra, former Indian ambassador to Russia, told Al Jazeera that the bilateral defence cooperation agreement “marks a move from an equipment-centric defence supply relationship to one that also enables operational logistics cooperation”.

“It adds a functional layer of interoperability that India did not previously have with Russia, thus bringing the bilateral relationship closer,” Malhotra said, adding that the pact provides New Delhi with “access to Russian facilities in the Arctic and far East, where Russia is a critical enabler”.

The strategic signal from the agreement “is one of continuity and depth as regards a trusted legacy partnership”, the former ambassador added.

He said that RELOS “diversifies risk by allowing India logistics access outside Western-controlled networks and it institutionalises such access in a modest yet concrete way”.

While hosting Russia in the Indian Ocean, India also gains access to the northern sea routes, countering China, which already has access, argued Singh of Jawaharlal Nehru University.

Praveen Donthi, senior India analyst at the International Crisis Group, a Washington-based think tank, said: “This builds and strengthens India’s access from the Pacific to the Arctic. As an important player with stakes in the Indo-Pacific, this comes as a shot in the arm for India.”

But didn’t India agree to diversify away from Russia?

India has been reliant on Russia for its military supplies for some time, and the majority of India’s arsenal is Russian-made.

Since the Cold War era, India has been among the leaders of the so-called “non-cooperation movement”, under which developing countries refused to take definitive sides in hostilities between Russia and the West. In recent years, India has come to refer to this cornerstone of foreign policy as its “multi-alignment” strategy.

But amid mounting US and European pressure – particularly US President Donald Trump’s decision to slap an additional 25 percent trade tariff on India for buying Russian oil last year – India has looked to diversify its defence and energy supplies, ramping up purchases from the West. All the while, it has continued with its delicate balancing act to maintain ties with Russia as well.

Through the RELOS agreement, New Delhi has offset its efforts to diversify away from Russia, said Singh.

“India is posturing that we are not disengaging by not buying more military hardware,” he added, “but we are proactively engaging you in strategic affairs.”

“That’s one trade-off that India has tried to make with Russia in this deal,” he told Al Jazeera. “RELOS gives Russia a low-cost logistics bridge into the Indian Ocean and extends its naval endurance, increasing its strategic leverage.”

Is there a lingering US shadow?

India also has military pacts with the US, including the Logistics Exchange Memorandum of Agreement (LEMOA).

Signed in 2016, LEMOA allows mutual access to military logistics and refuelling facilities, while another pact facilitates the sharing of encrypted and high-tech communication systems between the two militaries.

“The RELOS agreement gives Russia a sort of standing alongside the US with LEMOA,” said Singh. However, there is one major difference between the agreements: New Delhi has allowed Russia the stationing of troops, aircraft, and warships, which is not the case in any other agreement.

Since Trump returned to the White House in January last year, relations with New Delhi have suffered on multiple fronts, ranging from India’s foreign policy to punishing tariffs.

Andrey Kortunov, from the Russian International Affairs Council in Moscow, told Al Jazeera that the RELOS agreement is not essentially directed against the United States. “But it is a signal to Washington that America cannot take India for granted,” he added.

“Given signs of transactionalism in US foreign and economic policy, RELOS reinforces India’s strategic autonomy,” said Ajai Malhotra, former Indian ambassador to Russia.

The retired Indian diplomat further noted that from New Delhi’s perspective, partnerships with Moscow and Washington are not mutually exclusive and the “long-standing and deep-rooted friendship with Russia and our close ties with the US are not a zero-sum game, and never have been.”

The RELOS agreement is also “about future-proofing India’s strategic space, by providing an added degree of flexibility in a scenario where global alignments continue to churn and become more unpredictable,” said Malhotra.