Ukrainian officials pleaded with visiting U.S. lawmakers this past weekend to provide military aid, claiming their ousted president intentionally gutted the nation's defenses so it would be vulnerable to a Russian takeover, one of those U.S. lawmakers told Fox News.

"They wanted arms," the lawmaker said, "even recognizing that it could be cited by Putin as an excuse, a provocation for further military action by him. They said Putin's goal has never been Crimea; his goal is Kiev."

Even before Viktor Yanukovych's tenure as president, Ukraine's military was woefully underfunded and outdated. The nation's defense force is composed of obsolete tanks and fighter planes, and thousands of low-paid soldiers.

But the lawmaker who spoke with Fox News claimed Yanukovych had made it a point, over the course of his administration, to "hollow out" the Ukrainian military further.

The goal, the source said, was to weaken the Ukrainian national defenses in the event Russia eventually moved to reclaim the country.

Interim Ukrainian Prime Minister Arseniy Yatsenyuk told the visiting U.S. lawmakers that Yanukovych's policy had effectively left Ukraine with about 6,000 capable soldiers. Yatsenyuk and every other significant Ukrainian leader the U.S. congressional delegation met with all pleaded with the lawmakers to use their influence in Washington to supply small arms and ammunition to the Ukrainian government. The lawmaker said there was not unanimity amongst the members of the delegation about the wisdom of such a policy.

Over the weekend, Sen. Chris Murphy, D-Conn., a member of the delegation, would not give a definitive answer when asked whether military aid was on the table.

"I think there are a lot of ways that we can assist in the resistance. I'm not sure that we're to the point of providing arms, but they need all sorts of non-lethal assistance, like MREs, that we can put on the ground," he told ABC's "This Week."

But other lawmakers are more aggressive. Sen. John McCain, R-Ariz., while acknowledging that Ukraine is "militarily out-matched by Russia," called Monday for the Obama administration to provide military assistance.

"The Administration should rush the modest military assistance to the Ukrainian government that its leaders have requested," McCain said in a statement.

Vladimir Putin already has signed a decree recognizing Crimea as an independent nation, after the region voted in favor of joining Russia on Sunday.

The lawmaker who spoke with Fox News said that if the provision of arms and ammunition is not in the cards right now, the Obama administration should at least be announcing the dispatch of a U.S. military delegation to Kiev to assess the country's needs.

Yatsenyuk and other Ukrainian leaders were "very heartened" by recent statements from German Chancellor Angela Merkel indicating she may soon be amenable to a tougher stance on sanctions against Russia -- but the lawmaker said the Ukrainians emphasized repeatedly that Putin does not respond to words or threats, only to tough actions.

"There's a lot of reality-denying going on over here," the lawmaker told Fox News. "It's like, we didn't want a war against Al Qaeda, but they were at war with us. I hate to say it, but Vladimir Putin is engaged in his own Cold War with us."