The U.S. and its European allies are discussing potential responses if Russian President Vladimir Putin takes military action against Ukraine, including fresh sanctions on Moscow and further security assistance for Kyiv.

Senior U.S. officials have raised the idea of a package of measures in discussions with European counterparts over the past week, telling them the Biden administration is already working up a menu of options to counter possible moves by Russia, according to people familiar with the discussions.

The planning is at an early stage even within the U.S., and would require more discussions before seeking the support of other countries. But it comes after U.S. officials raised the alarm that Russia may be weighing a potential invasion of Ukraine as tensions flare between Moscow and the European Union over everything from migrants to energy supplies. The Kremlin denies any such intention.