WASHINGTON >> A senior administration official says Secretary of State John Kerry will travel to the Ukrainian capital of Kiev Tuesday to meet with government officials.

Kerry’s trip comes as the U.S. and other Western nations weigh a response to Russia’s military advance into Ukraine. Kerry has raised the possibility of issuing economic sanctions and visa bans, freezing Russian assets and levying trade and investment penalties.

The official says the U.S. now believes that Russia has complete operational control of the Crimea peninsula, a pro-Russian area of Ukraine. The official says the U.S. believes there are more than 6,000 Russian air and naval forces in the region.

The official was not authorized to publicly discuss the situation and insisted on anonymity.