Russia and the United States have still to agree over links to missile defence issues in the nuclear disarmament treaty, the chief of Russia's general staff said in an interview published Tuesday.

"The treaty is some 95 percent complete," General Nikolai Makarov told the Rossiyskaya Gazeta daily.

"We still have to resolve some issues, including getting the US agreement to include the missile defense issues into the treaty," he added.

"Whether the new treaty is signed, and how soon it will be, will depend on the sides' readiness to consider each other's interests," Makarov said.

Earlier this month, Boris Gryzlov, speaker of Russia's lower parliamentary chamber, the Duma, said it would not ratify a future nuclear disarmament treaty with the United States unless it dealt with the issue of missile defence.

Some observers have said that a Russian insistence on a link with missile defence is the main problem holding up agreement on a successor to the 1991 Strategic Arms Reduction Treaty (START) between the two countries.

Russia has already expressed concern after Romania said this month it would hold talks with Washington on hosting US missile interceptors, and Bulgaria showed an interest in taking part in a US missile shield.

This plan would be part of a replacement for a scrapped US initiative to place missile defence facilities in Poland and the Czech Republic, long a source of tension between Moscow and Washington.

US President Barack Obama and Russia's Dmitry Medvedev had targeted a new agreement by the end of 2009 to drastically reduce nuclear stockpiles, but negotiations dragged on into 2010.

But a joint press conference in Moscow last Friday, US Secretary of State Hillary Clinton and Russian Foreign Minister Sergei Lavrov were both upbeat about the chances of signing a new treaty.

Signed in 1991, START led to huge reductions in the US and Russian nuclear arsenals and imposed verification measures to build trust between the two former Cold War foes.