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.

The effort is also aimed at steering Putin away from further aggression on Ukraine by making clear there would be a strong and coordinated response, two of the people said. They declined to specify what might be included, but with heavy sanctions already on many parts of the Russian economy including its defense and finance sectors, one area left to attack might be energy. A White House spokesperson declined to comment.