INDIANAPOLIS | U.S. Sen. Joe Donnelly, D-Ind., warned Russian President Vladimir Putin Tuesday that he "risks setting off catastrophic events" if Russian forces advance beyond the Crimean Peninsula and invade Ukraine.
"Mr. Putin might not be aware of this, Mr. Putin might not care, but Ukrainians will fight, and will fight as soon as the Russians, if they do, come into one square meter of the Ukrainian mainland," Donnelly said. "If Russia crosses that line, I think they'll be getting into a swamp that would be very, very difficult for them to get out of."
The Hoosier senator, a member of the Senate Armed Services Committee, traveled to Kiev Sunday for meetings with Ukrainian Prime Minister Arseniy Yatsenyuk and other government officials.
Donnelly told reporters Tuesday that every Ukrainian he spoke with, from the highest government offices to people walking by on the street, vowed to fight if Russia invades.
"This is an extraordinarily serious situation," Donnelly said. "If Mr. Putin thinks this is going to be another Crimea, he's sadly mistaken."
Russian forces invaded the semi-autonomous Ukrainian region of Crimea Feb. 28, one week after the Ukrainian people ousted their pro-Russia President Viktor Yanukovych.
Crimea residents voted March 16 -- in a disputed referendum -- to declare independence from Ukraine and join the Russian Federation. Putin annexed Crimea two days later.
Donnelly said the United States "stands with the people of Ukraine," and indicated he will vote for legislation directing $1 billion in U.S. aid to Ukraine.
He also supports the economic sanctions imposed on Russian business and political leaders by President Barack Obama. He believes the United States should further punish Russian aggression by hitting its energy and financial sectors with additional sanctions.
"There are a number of very important steps that can be taken to send the message to Mr. Putin that you will suffer extraordinary financial damage," said Donnelly, who characterized Russia under Putin as a "thugocracy."
While Donnelly acknowledged Ukraine is far from Indiana, he said what happens there affects the lives of Hoosiers that he's sworn an oath to protect.
"It is a safer world when we are not in a position where we're wondering which country gets invaded next," Donnelly said.