Russian border guards have started recording the passport details of travelers crossing the Russia-Belarus border, the Belarusian human rights project Mayday Team reported.

The practice began at border crossings no later than April 30. Guards are requiring travelers to present their passports and logging the data into an Excel spreadsheet, creating lines at checkpoints.

“Russian inspectors are openly acknowledging that they have been given instructions to maintain constant monitoring of foreigners entering Russia and Russians leaving the country. These categories of travelers are required to personally approach the checkpoint windows and present their documents,” MayDay.Team wrote.

What is driving the checks — and whether they will become permanent — remains unknown.

In late April, it emerged that a Russian conscript who had received a draft notice was denied permission to leave the country through Belarus — the first known case of its kind. The Belarusian State Border Committee confirmed that it had stopped allowing Russian conscripts to cross the border, though some have still managed to get out.

On May 1, Ivan Lyubshin — a Russian national who had served five years in prison for an online comment and was attempting to emigrate — was detained at Minsk airport and returned to Russia, where a criminal case was opened against him for violating the terms of administrative supervision. Upon his release from prison, he had been required to remain under security services oversight for another eight years.

Kovcheg, a project that assists Russian emigrants, wrote that Belarus had until recently been the last destination for legal emergency departure for people barred from leaving Russia — due to debts, criminal prosecution, or refusal to serve in the military. Belarus is no longer a safe exit route, Kovcheg concluded.