The United States on Monday welcomed an offer from Albania to take in 210 members of an Iranian opposition group who currently live at a former US military base in Iraq.

Washington urged the People's Muhajedeen of Iran, or Mujahedeen-e-Khalq (MEK), to accept Tirana's "generous" offer immediately, State Department spokeswoman Victoria Nuland said.

She also thanked Albanian Prime Minister Sali Berisha "for the humanitarian gesture to provide a safe haven for these individuals."

"Albania has been a strong partner of the United States in the effort to bring stability and peace to Iraq," Nuland added in a statement.

A February mortar and rocket attack on Camp Liberty, near Baghdad, housing about 3,000 members of the MEK, killed seven people, according to the group.

Berisha announced that Albania would resettle for "humanitarian reasons" the 210 MEK members who live at Camp Liberty, after moving from their previous home in Camp Ashraf.

The UN envoy in Iraq, Martin Kobler, and US Deputy Assistant Secretary of State Barbara Leaf held talks Saturday with Albanian authorities over security measures and housing conditions.

"We further urge the MEK leadership to place the highest priority on the safety and security of the former residents of Ashraf through full and unconditional cooperation with the resettlement process," Nuland said.

A spokesman for the National Council of Resistance of Iran, a coalition including the MEK, has welcomed the offer but said it was nothing new as it had already been agreed in November and was also not enough.

The MEK was founded in the 1960s to oppose the shah and, after the 1979 Islamic revolution that ousted him, the group took up arms against Iran's clerical rulers.

It says it has now laid down its arms and is working to overthrow the Islamic regime in Tehran by peaceful means.

Britain struck the group off its terror list in June 2008, followed by the European Union in 2009 and the United States in September 2012.