Moscow considers any potential new sanctions related to chemical weapons imposed by the U.S. on Russia to be illegal and will respond accordingly once they are announced, Russian officials said Wednesday.

On Tuesday, the U.S. State Department said that it might impose another round of sanctions on Russia over the latter's involvement in the nerve agent attack on a former Russian spy in Britain in March.

"We consider these restrictions imposed by the United States on Russia to be illegal, and we will also treat accordingly similar steps if they follow," Kremlin spokesman Dmitry Peskov said.

Russian officials said that Washington is using far-fetched excuses to justify its plan of new sanctions, as it accuses Russia of failing to meet the terms of its Chemical and Biological Weapons Control and Warfare Elimination Act (CBW Act) of 1991.

"The reference to U.S. legislation, which Russia supposedly must comply with, looks dubious. Russia is not obliged to comply with any of the laws of the U.S.," Leonid Slutsky, head of the State Duma's international affairs committee, was quoted as saying.

He underlined that Moscow fully adheres to its international obligations and has already completely destroyed its reserves of chemical weapons on its territory.

The lack of arguments for the introduction of new sanctions against Russia makes U.S. politicians look for "convincing evidence" of Moscow's guilt where it is absent and cannot be found, Slutsky said.

Nevertheless, Russian officials said the possible sanctions would not exert major influence on Russia.

Deputy Finance Minister Sergei Storchak said Russia's national and institutional investors have learnt to deal with possible risks on the national debt market via previous experience, and that the country has enough reserves to tackle issues of the federal budget deficit.

"Wherever it is possible, we will challenge the actions of the Americans," Storchak said.

He added that Russia has platforms where it can respond efficiently to possible sanctions, such as the G20 and the Financial Stability Board.

"Nothing critical will happen. I'm sure of it. But all of this is unpleasant and, of course, will force us to make certain decisions," Russian Prime Minister Dmitry Medvedev was quoted by RIA Novosti news agency as saying.