MOSCOW, June 25 (RIA Novosti) - Russia does not rule out the possibility that the U.S. and Lithuania are holding informal talks over the deployment in the former Soviet state of elements of a U.S. missile defense system, Russia's foreign minister said on Wednesday.

"We have received no official answer from the U.S. to our question concerning missile defense system talks with Lithuania. Unofficially, they have been telling us that 'no, no, we still want the missile interceptors to be deployed in Poland, but as talks with Poland are going slowly, we are keeping in mind some reserve options,'" Lavrov told journalists.

"Anything official starts off unofficial. There is no smoke without fire," he added.

Moscow strongly opposes the possible deployment by the U.S. of 10 interceptor missiles in Poland and a radar in the Czech Republic as a threat to its national security. Washington says the missile defense system is needed to deter possible strikes from "rogue states."

Lavrov also said that Moscow's main concern remained Washington's plan to deploy the missile system, irrespective of where in Europe it may eventually be stationed.

"This is a strategic error when we consider that there is a unique chance to establish a genuine joint defense system between Russia, the U.S. and Europe against rocket threats. This chance is now disappearing before our eyes due to the U.S. administration's obsession with this unilateral project - one which they are imposing on NATO countries and the whole of Europe in general," he said.

Poland's deputy foreign minister said last week that Washington and Vilnius were holding missile defense talks. "Lithuania's defense minister proposed it himself in May," Witold Waszczykowski said.

Both the U.S and Lithuania denied the report.

Poland has taken a tough stance in the missile talks with the U.S., demanding it upgrade its air defense systems in return.

The missile defense plans were also discussed at a meeting between U.S. President George Bush and Russia's then-president, Vladimir Putin, in the Russian Black Sea resort of Sochi in April.

However, Lavrov reiterated that Moscow and Washington had been unable to come to any kind of understanding on the issue, despite a U.S. pledge after the Sochi meeting to offer measures to boost trust and transparency in a bid to ease Russian concerns.

The Russian foreign minister had previously said that, "Dialogue has stalled. Every new meeting indicates that the proposals being made [to allay Russian fears] are shrinking and becoming less convincing."