The office door of rights group Amnesty International is sealed off in Moscow, Russia, November 2, 2016. (Maxim Zmeyev/Reuters)

Authorities abruptly locked out staff of the Russian branch of Amnesty International from their Moscow office on Wednesday, amid concerns about widening crackdowns on human rights groups and others.

A statement from Moscow’s city administration, whose land department owns the building containing Amnesty’s offices, said the rights watchdog group had failed to pay rent on time and that staff should remove their belongings and clear out. 

But Amnesty officials denied that there were any problems with rent, which raised questions about whether the eviction was linked to pressures in Russia against groups perceived as challenging the government.

Sergei Nikitin, director of Amnesty’s Moscow office, said staff members found a seal on the door to the office, where the locks were changed and power was cut. A note on the seal warned against entering the property.

The development comes as human rights groups in Russia face increasing government controls and, in some cases, harassment. It also follows a strongly worded protest that Amnesty issued Tuesday over the incarceration and treatment of a Russian human rights activist.

Sergei Nikitin, Director of Amnesty International representative office in Russia, talks to journalists in Moscow, Russia, November 2, 2016. (Maxim Zmeyev/Reuters)

John Dalhuisen, Amnesty International’s Europe director, called the lockout “an unwelcome surprise.”

“Given the current climate for civil society work in Russia, there are clearly any number of plausible explanations, but it’s too early to draw any conclusions,” Dalhuisen said.

Nikitin told reporters outside the office that Amnesty had always paid the rent on time and had the documents to prove it. The organization has rented the building for 20 years. 

He planned to take up the matter with Moscow authorities.

The Moscow city property department cited “considerable violations of the terms of the lease agreement” and said Amnesty was warned that the lease could be terminated — charges that Nikitin repeatedly denied Wednesday.

President Vladi­mir Putin’s spokesman said he was unaware of the incident.

“This is the first time I’m hearing about this. I have absolutely no information of the sort,” Kremlin press secretary Dmitry Peskov told reporters.

On Tuesday, Amnesty International demanded that authorities release Ildar Dadin, a street protester convicted of participating in “unauthorized” assemblies, and investigate his allegations of torture. Dadin’s letter from prison to his wife, in which he described being beaten repeatedly, was published Tuesday by the Meduza online newspaper, a Russian-language news site based in Riga, Latvia.

Human rights groups that have criticized Russian authorities have faced what activists describe as an official campaign of harassment. Some nongovernmental organizations that work in Russia and receive funding from abroad have been designated as “foreign agents,” which gives Russian prosecutors the power to shut them down if deemed “undesirable.” 

In September, the independent Levada Center polling group was designated a foreign agent, prompting its leaders to say they might have to close their Russian operations.

Various rights activists have also encountered a backlash from apparent pro-Kremlin vigilantes.

Last month, masked men carrying pistols, knives and truncheons stormed a Greenpeace campsite and severely beat volunteer firefighters in southern Russia.

In May, a group wearing the traditional hats of Cossacks assaulted a group of anti-corruption activists at an airport in southern Russia.

In Moscow, where many buildings are owned by the city, sudden termination of lease agreements has been used as a way of putting pressure on organizations that are critical of authorities. In 2014, the lease of the experimental theater group Teatr.doc was abruptly terminated.

Natalya Abbakumova contributed to this report.