President Obama is still deciding whether or not to sign a bill that would authorize new sanctions on Russia, a senior administration official said Monday.

While the administration remains “deeply concerned” about Russia’s actions in Ukraine, it has not made a decision yet on whether to add more sanctions. The administration official said the U.S. must maintain a united front with allies and look for ways to minimize the impact additional sanctions would have on U.S. business as well as oil markets.

Last week, Congress passed a bill that authorized – but does not legally require – the U.S. to supply lethal weapons to Ukraine.

The current legislation authorizes $350 million worth of weapons to the war-torn country.

The Ukraine Freedom Support Act passed both chambers of Congress Thursday but a technical issue caused it to return to the Senate for a vote Saturday night.