Sen. Bob CaseyRobert (Bob) Patrick CaseyBipartisan group of lawmakers aim to reform US sugar program Scarborough: 'Washington would be melting down' if shooter was 'named Muhammad' Dems renew calls for gun control in wake of Texas church shooting MORE Jr. (D-Pa.) said Sunday that Crimea’s vote was not “free or fair” and demanded that Congress take action.

“Today’s vote in the Crimea region of Ukraine is a wholly illegitimate scheme designed to provide some justification for Russia’s continued aggression,” Casey said. “A vote is in no way free or fair if it is held at gunpoint.”

On Sunday, Crimea voted to secede from Ukraine and join Russia after Russian troops invaded the region. Russian President Vladimir Putin said it was necessary to deploy troops to the region to protect Russian-speaking Ukrainians after the Kremlin-backed leader of Ukraine was ousted. But most of the international community, including the United States, has balked at that excuse and demanded Russia stop.

The House has passed a $1 billion aid package for Ukraine to help protect its democracy and independence from Russia. The Senate is expected to take up a different bill when it returns from a weeklong recess that also includes sanctions against Russia.

After the vote in Crimea, several lawmakers said it was important to pass a package that actually has consequences for Russia.

“I expect Congress will come together on an aid package for Ukraine that will show our nation’s robust support for the Ukrainian peoples’ legitimate aspirations for democracy and freedom,” Casey said. “If Russia continues to flagrantly flout international norms then Congress will be forced to consider additional economic and diplomatic measures. This type of aggression cannot be tolerated in the 21st century.”