Spanish police have warned that Islamist terrorists could exploit the government's mass migrant legalisation programme, as reports of lost passports and identity documents surge among applicants. 

Spain's socialist Prime Minister Pedro Sanchez approved a major initiative last month to grant legal status to half a million undocumented individuals, causing significant political backlash and triggering a 'collapse' in social services across the country.

And now, an internal memo from the National Police's General Commissariat for Immigration and Borders revealed that complaints over missing documents have continued to rise sharply among migrants seeking to benefit from the scheme.

According to the document, seen by Spanish outlet La Gaceta, the most dramatic increases in lost document reports have been recorded among Pakistani, Algerian and Moroccan nationals. 

Police noted that the nationalities most frequently linked to the missing document complaints overlap with profiles that have previously appeared in investigations related to Islamist extremism.

The internal document orders officers to intensify identity and background checks in these cases because of what it describes as the difficulty - and in some instances impossibility - of reliably confirming applicants' true identities.

The issue is unfolding while Spain remains under its long-standing level four anti-terrorism alert - one step below the maximum. 

Official figures from Spain's Interior Ministry show that more than 100 arrests linked to jihadism were carried out in 2025, marking the highest annual total since the 2004 Madrid train bombings.

Officers also pointed to previous intelligence warnings concerning potential infiltration routes into Spain. 

In January last year, an internal report from the General Information Commissariat warned that Pakistani Islamist terrorists could attempt to exploit the Canary Islands migration route.

The suspected dangers materialised in March 2025 with the police dismantling a Barcelona-based cell affiliated with ISIS. The operation resulted in the arrest of several Pakistani nationals.

Spanish authorities have also dismantled multiple jihadist networks in recent years involving suspects - particularly Algerians and Moroccans - who entered the country illegally.

Internal Interior Ministry reports over the past decade have consistently placed Moroccan nationals at between 40 and 50 per cent of those arrested for Islamist terrorism offences in Spain.

The internal memo stated that the combination of rising lost document reports and the regularisation process is creating 'a concrete operational concern.'

It warned that 'rigorous identity verification is compromised,' adding that this 'increases the risk that individuals linked to Islamist terrorism could obtain legal documentation without the usual checks.'

Under current internal protocols, the National Police require officers to carry out detailed investigations before accepting any report of lost documentation in order to confirm an applicant's identity and rule out national security risks.

Police background reports are expected to play a major role in assessing thousands of applications in the coming months.

Over the past few weeks, thousands of migrants have been waiting hours at more than 400 locations across the country for appointments after submitting applications.

Migrants have been pictured in long queues outside registry offices in regions such as Catalonia, Andalucia and Madrid.

It emerged late April that many of these individuals may have obtained legal status without providing a criminal record certificate.

For the first five days of the mass regularization process, postal clerks were forced to use a training manual containing errors.

The manual, seen by Spanish news outlet ABC, does not state that submitting a criminal record certificate is mandatory for undocumented immigrants who have worked during their stay in Spain or who currently have a valid contract. 

Consequently, some migrants may have submitted incomplete documentation.

And officials in Spain have warned of a collapse in social services as thousands of migrants attempt to gain legal status.

Municipal unions in Seville last month warned that 'extraordinary pressure' and overcrowding are lowering service quality and creating high tension among staff and the public in the Andalusian city.

Unions are pleading for more staff, an improvement in security, and compensation for workers forced to face the chaos.

In Spain's capital, Madrid, services are also under mounting pressure.

'We've gone from 1,500 daily requests at social services centres to 5,500. I think a hasty decision was made, perhaps even intended to create a collapse,' said Jose Fernandez, the municipal delegate for Social Policies.

Fernandez explained to news outlet 20minutos that the process was launched 'without consulting the relevant authorities.'

Meanwhile, tensions have been rising as the crowds have overwhelmed registry offices and those seeking to confirm their legal status have begun to grow restless. 

Violence erupted in the city of Murcia late last month, with video footage capturing a chaotic brawl among a group of male migrants while hundreds looked on, with long queues lining the nearby buildings.

Police union representative Adrian Rodriguez said the chaos occurred due to growing pressure in the queue, with large numbers of people waiting to be seen.

And earlier that week, a group of desperate migrants scaled the walls of the Gambian embassy in Madrid after being unable to secure the vulnerability certificates needed for their applications.

Many had spent the entire night queuing outside the building just to obtain the required documentation.

However, they were informed that morning that all appointments were already booked.

The situation then spiraled out of control as migrants began jumping over the embassy fence in a desperate bid to obtain their certificate.

The government's amnesty is a central plank of Sanchez's progressive agenda to harness the economic benefits of migration for its ageing population, even as other European governments move to tighten their borders.

Sanchez argues immigrants are key to Spain's economy, which expanded 2.8 per cent last year - more than twice the average expected in the entire eurozone.

'Spain is ageing... Without more people working and contributing to the economy, our prosperity slows, and our public services suffer,' he wrote in an open letter addressed to citizens.

However, the initiative has faced intense backlash from Spanish right-wing parties, with opposition Popular Party deeming the drive reckless.

And Santiago Abascal, the leader of the populist hard-Right party Vox, accused the Socialist-led coalition of accelerating what he called an 'invasion'.