An armed group stormed a police station in Armenia's capital Yerevan on Sunday, killing one policemen and taking more hostage, demanding the release of a jailed opposition leader and the resignation of President Serzh Sarkisian.

The presidency said security forces were in "full control" of the situation, but the drama was still going on after about 12 hours and police said they were holding talks with the gunmen.

"The police have the necessary means and we will take pre-emptive, swift action to liquidate them if they do not listen to our calls," Hunan Pogosyan, a deputy police chief, told journalists.

The attackers said they were demanding the release of Zhirair Sefilyan, an opposition politician arrested last month for alleged possession of firearms and who was accused in the past of plotting a violent overthrow of the government.

They issued a video showing several men in flak jackets and armed with Kalashnikovs as well as several hostages being held inside the police building and issued a statement calling for Armenians to take to the streets.

One of the gunmen said on social media that the hostages included two senior police chiefs.

Armenia's National Security Service said one policeman was killed and two others wounded after the gunmen stormed the station in Yerevan's Erebuni district at dawn and held a number of hostages "under the threat of violence".

"The law enforcement agencies are in full control of the situation and are taking all the necessary measures to resolve it," the presidency said about 12 hours after the standoff began.

Nikol Pashinyan, a lawmaker who met the hostage-takers, told journalists that the group was holding eight officers hostage but had released one who was suffering from high blood pressure.

"We demand the release of Zhirair Sefilyan, we will only obey his orders. Sarkisian must resign," one of the group's members, Varuzhan Avetisyan, wrote on Facebook.

He said Armenia's deputy police chief General Major Vardan Egiazaryan and Yerevan deputy police chief Colonel Valeri Osipyan were among the hostages.

- 'Take to the streets' -"We are doing this for you. People, take to the streets!" one of the gunmen, Areg Kuregyan said in the video. "We demand the release of all political prisoners."

"Join us! For now, we are holding the positions. We will stand as long as we can," another gunman said in the video statement.

Military and police cordons were blocking streets around the Erebuni station with vehicles including an armoured personnel vehicle, an AFP photographer witnessed.

Sefilyan, the leader of small opposition group the New Armenia Public Salvation Front, and six of his supporters were arrested in June after the authorities said they were preparing a plot to seize government buildings and telecommunication facilities in Yerevan.

A fierce government critic, Sefilyan was arrested in 2006 over calls for "a violent overthrow of the government" and jailed for 18 months. He was released in 2008.

Last year, Sefilyan and several of his supporters were arrested again on suspicion of preparing a coup, but released shortly afterwards.

An ethnic-Armenian, he was born in Lebanon where he fought in the civil war in the 1980s, defending Beirut's Armenian Quarters.

He then moved to Armenia to take part in the 1990s war with neighbouring Azerbaijan for control of the Armenian-populated separatist region of Nagorny Karabakh.

Sarkisian, a shrewed former military officer, has been president of the tiny country of 2.9 million people since winning a vote in 2008 that saw bloody clashes between police and supporters of the defeated opposition candidate in which 10 people died.