MOSCOW -- The head of a doctors' union that has criticized the Russian government’s response to the coronavirus pandemic has been detained during a trip she made to assess the preparedness of provincial hospitals and supply medical workers with masks and other safety equipment.

Anastasia Vasilyeva of the Doctors' Alliance, a group backed by Russian opposition leader Aleksei Navalny, was stopped by the police in the town of Okulovka, some 400 kilometers north of Moscow, and held overnight for questioning, a representative of the labor union told RFE/RL.

A video posted on the Twitter account of the Doctors' Alliance late on April 2 appears to show Vasilyeva being detained by police in a rough manner.

"Police ambushed Anastasia Vasilyeva, and tried to drag her by force into the police station," reads a text appended to the video, alleging that Vasilyeva had lost consciousness after one of the officers tried to strangle her. "This is real fascism."

Ivan Konovalov of the Doctors' Alliance told RFE/RL on the phone that Vasilyeva was driven to a local police station in an unmarked vehicle.

After a brief court hearing on April 3, she was fined 1,600 rubles ($21) for violating the rules of a lockdown imposed by Russian authorities on March 30 and disobeying police orders.

Amnesty International denounced Vasilyeva's arrest in a statement on April 3 saying it was "staggering that the Russian authorities appear to fear criticism more than the deadly COVID-19 pandemic."

Since Russia began reporting a spike in coronavirus cases in early March, Vasilyeva has criticized the government's response to the epidemic and accused it of downplaying the number of infections in Russia.

"The government is openly lying," she told RFE/RL on March 20, alleging that the authorities "don't want people to understand the dire state that our health care is in."

The Doctors' Alliance trip to the Novgorod region was part of a campaign it dubbed the All-Russian Medical Inspection, a tour of the country's hospitals to assess their preparedness for the coronavirus epidemic and provide medical workers with equipment to weather the coming storm and ensure the local population has sufficient health care.

"We'll travel the length of Russia to inspect medical facilities and bring protective equipment to doctors in those places, where the government can't provide it," Vasilyeva said in a promotional video for the campaign.

Konovalov, the spokesman who was with Vasilyeva in Okulovka and spoke to RFE/RL from outside the police station where she was being questioned, said the union had traveled to the Novgorod region in a group of 12 people, including a lawyer and three camera operators tasked with documenting the trip.

The medical equipment they were transporting had been partly bought through public donations. Konovalov said the Doctors' Alliance had gathered 3 million rubles ($40,000) since announcing its funding drive on Monday afternoon.

"This is a pretty big sum considering our labor union is small and the country is going through an economic crisis. The ruble has depreciated and oil prices have plunged," he said.

Konovalov insisted the group was taking precautionary measures, wearing face masks and traveling three people to a car. He said they were unsure if they'll continue visiting hospitals in Russia's regions after Vasilyeva’s detention and fine.

"We'll have to discuss that," he said. "We don't want to abandon this mission."

Igor Trunov, the head of the Moscow branch of the Red Cross, said in a press conference on March 26 that at least 17 Russian regions were short of ventilators and other vital medical equipment.