Russia and China want countries neighboring Syria to inform the U.N. if they find any extremist group trying to get chemical weapons, warning that they may be used in Europe.
Both countries sent a draft resolution through the Security Council Wednesday, saying terrorists are a "clear and present threat" to the continent.
"We know that there is a strong concern, with reports that thousands of them have moved to Europe," Russia’s U.N. Ambassador Vitaly Churkin told reporters in New York.
"Could some of them have brought with them the components of chemical weapons? Could some of them have brought to a European city or European country their knowledge of how to build chemical weapons?" he asked.
The resolution would call on such countries as Turkey and Iraq to monitor extremists for any moves toward building or acquiring chemical weapons.
Some Western diplomats call the resolution a distraction from a U.N. investigation into the use of chemical weapons on civilians outside Damascus in 2013. Hundreds of people died as a result of the attack, even though an exact casualty number has never been established.
Both the Assad government - a major Russian ally - and the opposition blame each other for the attack which violated international law.
The United States has said chemical weapons were released from helicopters and stresses that only the Syrian army has such aircraft, not the opposition.