Russian state-owned aerospace group United Aircraft Corporation plans to bid for a 35-billion-dollar US Air Force tanker contract, teaming up with a US partner, a lawyer representing UAC said Friday.

"They're going to announce Monday a joint venture with an American company to bid on the tanker program," attorney John Kirkland told AFP.

Kirkland did not identify the the US firm except to say its shares were publicly traded.

The Department of Defense (DoD) could not immediately confirm the apparent upcoming Russian bid.

"We've always been clear that this is a fair and open competition and we welcome all qualified bidders," said Geoff Morell, a Pentagon spokesman.

According to a source familiar with the situation, UAC will propose a tanker version of its Ilyushin IL-96.

The plane, which would be called the IL-98, is roughly the same size as the 767-based tanker proposed by Boeing but with operating costs in line with the Boeing KC-135 tankers currently used by the air force.

The tanker would be built in Russia and assembled in the US southeastern regoin, the source said.

The announcement was the latest twist in the long-running 35-billion-dollar tanker contract saga to replace the air force's aging fleet of 1950s-era planes.

US aerospace giant Boeing is the only company that has announced it will bid for the 35-billion-contract to supply the air force with 179 aerial refueling tankers.

EADS, the parent of Boeing's arch-rival Airbus, said earlier Friday it was considering a bid for the contract after the Pentagon signaled a flexible deadline to accommodate the European aerospace group.

The Pentagon, meanwhile, said that EADS was seeking a 90-day extension of the deadline.

"They've indicated to the department that they would like to see us extend the time frame 90 days," Pentagon spokesman Bryan Whitman said Friday. The tendering process is due to close around mid-May.

"We would consider reasonable extensions," Whitman said, adding that the "next step is for them to give us some specifics in terms of what they need the additional time for."

EADS North America's spokesman Guy Hicks declined to comment on Whitman's remarks and referred questions back to the Pentagon.

Just last week EADS was forced to withdraw from the bidding after its lead partner, US defense contractor Northrop Grumman, refused to compete, alleging the requirements unfairly were skewed toward Boeing's smaller aircraft.

UAC was launched in 2006 under the administration of then-president Vladimir Putin.

The UAC move Friday coincided with talks in Moscow between US Secretary of State Hillary Clinton and Putin, the Russian prime minister.

Putin lamented that bilateral trade had plummeted in 2009 as a result of the economic crisis to 16 billion dollars, from 36 billion dollars, although he said the economic potential of the US-Russia partnership remained high.

"I appreciate you raising the economic relationship because we are committed to broadening and deepening ties between our two economies, our business leaders and investors," Clinton said.