"The proposals have been received and are being studied," Sergei Kislyak said.
U.S. Defense Secretary Robert Gates and Secretary of State Condoleezza Rice put forward proposals at a meeting Tuesday to ease Moscow's concerns, and said the plan would be finalized in writing by the end of the day; the papers were handed to Russia on Wednesday.
The top diplomats and defense chiefs failed at the talks in Moscow to reach an agreement on Washington's plans to deploy a missile shield in Poland and the Czech Republic, which Moscow views as a threat to its own security, but both sides agreed to continue negotiations.
Russian Defense Minister Anatoly Serdyukov said Tuesday the '2+2' talks had shown the sides' positions remained unchanged, but Foreign Minister Sergei Lavrov called the new proposals put forward by Rice and Gates "useful and important."
After the last round of talks between the four ministers in October 2007, the U.S. sent written proposals that Russia said contradicted the agreements reached at the discussions.
On Tuesday, Rice admitted that there had been some discrepancies between the conceptual ideas put forward at the October meeting and the subsequent written proposals.
