As President Barack Obama waits to see how effective European-led negotiations are in quelling the conflict between Russian and Ukraine before deciding to send weapons to Kiev, Sen. John McCain spoke out Monday saying that the president's refusal to arm Ukraine would be a "shameful" time in American history.

"5,000 Ukrainians have been murdered, the first time since the end of World War II that one country has dismembered a nation, in Europe and to not give them weapons to defend themselves will go down as one of the shameful chapters in American history," the Arizona Senator told Fox News' Sean Hannity Monday night, according to The Daily Caller.

As for "the chancellor of Germany and the president of France," McCain added, "they should be ashamed too."

Obama said Monday that he plans to wait for the outcome of European-led peace talks this week before deciding whether to provide lethal weapons to the Ukrainian government, reported The New York Times.

"If, in fact, diplomacy fails, what I've asked my team to do is to look at all options," Obama said. "What other means can we put in place to change Mr. Putin's calculus? And the possibility of lethal defensive weapons is one of those options that's being examined."

Many European countries, including Britain, Germany and France, are hesitant to throw their support behind arming Ukraine, fearing that such a move could make the conflict worse.

A close ally of Russian President Vladimir Putin warned the European Parliament that an "all-out war" could erupt if the U.S. decides to arm the Ukrainian government, BBC reported.

Alexei Pushkov, a leading Russian MP and target of U.S. sanctions, said that American weapons could "expand the war and turn it into a real threat to the whole European security system."

Pushkov compared the situation to Vietnam, saying, "First they sent weapons, then they sent military advisers, then troops to protect military advisers, then troops to fight the Vietnamese."