KYIV, Dec 21 - Ukraine's armed forces are heavily outnumbered and outgunned by Russia's but could put up a level of resistance that would force Russian President Vladimir Putin to pay a price of many thousands of Russian lives for any new invasion, Reuters reported.

The Biden administration is weighing whether the United States could back insurgents in Ukraine should Russian President Vladimir Putin invade, according to a report in The Washington Post.

The report cites a "knowledgeable official" and describes how the administration is studying whether the U.S. could provide weapons, potentially including anti-aircraft missiles, and "other support to the Ukrainian military to resist invading Russian forces," as well as "similar logistical support to insurgent groups if Russia topples the Ukrainian government and a guerrilla war begins."

Western military analysts say Ukraine's army is better trained and equipped than in 2014, when Russia captured the Crimean peninsula without a fight, and highly motivated to defend the country's heartland.

For those reasons, they see it as highly unlikely that Putin would contemplate an outright conquest of Ukraine.

"We won't see a big giant red arrow going across Ukraine. I don't believe the Russians have the capability to just completely overrun Ukraine and take over the whole country, nor do I think they want to," said Ben Hodges, a retired U.S. lieutenant general now with the Center for European Policy Analysis.

A plausible alternative, he and others said, was that Russia might push south and west from Ukraine's Donbass region - already controlled by pro-Russian forces - to link up with annexed Crimea and the Black Sea. But even that more limited objective would entail high Russian casualties.

Siemon Wezeman, an arms specialist at the Stockholm International Peace Research Institute, said the scale of resistance to any invasion would dwarf anything Russia had faced in previous military operations in Chechnya in the 1990s or in its short war with Georgia in 2008.

"Yes it can defeat, say, the high level of Ukrainian forces, but try to invade a country like Ukraine with a population that is clearly against you, which is armed to the teeth, where most males have at least rudimentary military training that they can still remember. You're going into an area which is Chechnya multiplied by 10, or Georgia multiplied by 30," he said.

"It's not going to be a walkover. And then you have to defend to your own population as Russian president that you just suffered 10,000 losses in the first few days because you were stupid enough to support the Donbass rebels. I don't think that's going to resonate very well in Russia."

According to the Washington Post, a Biden administration task force is examining how assistance could be provided in a way that wouldn't violate any domestic or international laws.

President Biden previously said that sending U.S. troops to Ukraine is "not on the table," CNN reports. He also said he warned Putin that should the Russian president invade Ukraine, "there will be severe ... economic consequences like none he's ever seen or ever have been seen." (om/ez)