In Russia, a cream pie smudged in the face is no joke. Bizarre as it sounds, opposition activists get "pied" as part of sinister threats to stop their anti-government campaigning, or else.

Mikhail Kasyanov, a former Russian prime minister and leading opposition figure was at a restaurant one night this month when two men burst in: one shoved a pie in his face shouting, "Traitor" and "Agent of America" while the other filmed it.

'The situation is worsening every day. Putin is squeezing the whole political environment in Russia.' - Mikhail Kasyanov, opposition leader

"The situation is worsening every day," Kasyanov said. "Putin is squeezing the whole political environment in Russia. We have permanent blackmailing of the opposition.

"We face problems every day. Secret service coming asking, 'Why you are part of this opposition? You should be worried about your job or your son's place in university,' trying to imply the opposition is something dangerous." 

Alexei Navalny

Alexei Navalny is one of several opposition activists to get a piece in the face, a form of threat by Putin supporters. He posted this photo on Facebook after the attack. (Facebook)

This week, Alexei Navalny, another high-profile opposition leader, became the latest victim of the pie threat. He was pied at the headquarters of his anti-corruption foundation. Navalny tried to ridicule the prank, posting a picture on Instagram of himself smiling, with bits of cream clinging to his face, surrounded by supporters.

But the climate for those who question the current government is anything but playful. 

March will mark 1-year anniversary of Nemtsov killing

This weekend, thousands of people are expected to march in memory of Boris Nemtsov, a Putin critic who was gunned down one year ago. Nemtsov was a frequent critic of corruption in the Putin government and the 2014 Sochi Olympics.

Last Feb. 27, he was walking late at night with his girlfriend across a bridge close to the Kremlin when an assailant in a car shot him four times in the back.

Boris Nemtsov-bridge

Saturday's march was intended to go past the spot where Nemtsov was killed, but Moscow authorities rerouted it. (Susan Ormiston/CBC)

Five men, all Chechens, are in jail charged with the crime. A sixth, suspected of organizing the assassination, is being sought by authorities. Investigators say they've wrapped up their probe. A trial will come later. 

But many suspect the order to kill Nemtsov came from much higher up.

"All roads lead to Chechnya," said Kasyanov.

This week, a Russian activist released a stinging report on Chechnya's leader, Ramzan Kadyrov, who describes himself as a "Putin soldier" and runs his own large militia.

Ilya Yashan of the liberal opposition party PARNAS has no doubt about his role in Nemtsov's death.

"Kadyrov is behind the killing of my friend, Nemtsov," he says bluntly. 

Kadyrov has 'traitors' in his sights

Kadyrov has recently ratcheted up the tone of his attacks on the opposition.

He posted on Instagram a picture of Kasyanov and another activist in the crosshairs of a rifle. His deputy followed up with a photo of a large snarling hound apparently "itching" to get at the opposition.

Mikhail Kasyanov

'The situation is worsening every day,' says Mikhail Kasyanov, leader of the liberal PARNAS party. (Corinne Seminoff/CBC)

Kadyrov in the past has warned Russians of a "fifth column" of traitors threatening to destabilize the country, and the names of those who fall into that camp are on a list.

Kasyanov's name tops the list.

"That's how they call me," he says wryly, "Enemy No. 1. That's why they follow me everywhere trying to create further pressure on me and my family, but I have no thoughts to change my activity, to leave Russia. We continue our fight."

Targeting Russia's opposition1:10

Parliamentary elections are scheduled for this fall. Kasyanov and his team are beginning to campaign now, knowing they don't have the advantage of much television coverage, increasingly controlled by the state.

In the year since Nemtsov's death, Russia's economy has been in free fall. Revenues from oil, which made up more than 50 per cent of Russia's budget, have plummeted. Inflation has risen, international sanctions have pushed up the costs of some goods, and wages in some cases are delayed or not paid. 

Russia-opposition-protest

A protester hurls fake U.S. dollars at Ilya Yashin during a Moscow news conference by members of the opposition.A frequent accusation against opponents of the government is that they are 'agents of America.' (Jean-Fran├žois Bisson/CBC)

Normally, that would promote pressures on a sitting government.

Kasyanov thinks this is the year to bolster the opposition's poor showing in the polls. 

"It's a crucial year. Mr. Putin should make a decision: either he starts relaxation of the environment and allows elections to take place in a free manner or he continues to squeeze, to create a stronger fear among people," Kasyanov said.

March rerouted away from kill site

Ahead of Saturday's memorial for Nemtsov, his supporters had a bold but fruitless plan to try to get the bridge on which he was killed renamed Nemtsov Bridge. Not surprisingly, the initiative failed.

Mikhail Kasyanov (left) and Boris Nemtsov

Kasyanov, left, and Nemtsov in 2014. Nemtsov was killed Feb. 27, 2015, and some members of the opposition believe it was on the orders of pro-Putin Chechen leader Ramzan Kadyrov. (PARNAS)

Saturday's march, which scheduled to begin at 2 p.m. Moscow time, was to go past the spot where Nemtsov died, stopping at a small but persistent shrine, regularly fortified by flowers. But the route was disallowed by Moscow officials, who rerouted the march away from the bridge.

New regulations, organizers were told, forbid public activities on bridges.