Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty in speech denouncing West

Russian President Vladimir Putin signed a law with amendments to the Russian Criminal Code imposing more severe punishments for the crimes of desertion, looting and surrender during periods of mobilization and martial law, according to the official portal of legal information.

The law introduces the notions of "mobilization," "martial law" and "wartime" and adds a number of new articles to the Criminal Code.

This comes days after Putin announced a mobilization expected to draft more than 300,000 Russians with military expertise. Anti-war protests have broken out in response to news of the draft and many have tried to flee Russia.

The article criminalizing "looting" has been amended to provide for up to 15 years of imprisonment. Commission of the crime "during a period of mobilization or martial law, in wartime" is deemed an extenuating circumstance.

Failure by a subordinate to obey an order issued by a superior in due manner during a period of martial law, in wartime or in conditions of an armed conflict or the conduct of hostilities, as well as a refusal to participate in military action or combat, will be punished by imprisonment of two to three years. If severe consequences ensue, such actions will be punished by three to ten years of imprisonment.

Furthermore, reservists will be criminally liable for arbitrary abandonment of a unit or base and for failure to report for duty in due time without a good reason during their recruit military training. This acts will be punishable with up to 10 years of imprisonment, depending on the severity of the act.

The law also introduces a number of articles regarding a failure to execute a state defense order and a violation of the terms of a state contract.

President Joe Biden issued a statement Friday evening again calling the referendums in Russian-controlled Ukrainian territory a "sham."

"The United States will never recognize Ukrainian territory as anything other than part of Ukraine," he said in his statement.

Biden added that the U.S. "will work with our allies and partners to impose additional swift and severe economic costs on Russia."

He said the U.S. will join with other nations "in rejecting whatever fabricated outcomes Russia will announce."

-ABC News' Ben Gittleson

White House press secretary Karine Jean-Pierre declined to comment on reports that the U.S. has sent private warnings to Russia over its nuclear threats.

During her on camera briefing with reporters, Jean-Pierre she said the threats still haven’t given the U.S. reason to adjust its own nuclear posture.

“We obviously take these threats very seriously,” she said. “But we have not seen any reason to adjust our own nuclear posture at this time."

Jean-Pierre also declined to say if the President Joe Biden would support providing asylum to Russians fleeing conscriptions.

“What we're seeing in Russia, especially with the protests, and what we're seeing with Russians leaving their country is that this is an unpopular war,” she said.

-ABC News' Ben Gittleson

President Joe Biden and other Group of 7 leaders condemned Russia's "sham referenda" in occupied Ukrainian territories, calling it a Russian attempt to "create a phony pretext for changing the status of Ukrainian sovereign territory."

“These actions clearly breach the United Nations Charter and international law and go diametrically against the rule of law among nations,” the leaders said in a joint statement.

The G7 also pledged to "never recognize these referenda which appear to be a step toward Russian annexation and we will never recognize a purported annexation if it occurs."

They added, "These sham referenda initiated today by Russia and its proxies have no legal effect or legitimacy, as demonstrated by Russia’s hasty methods of organization, which in no way respect democratic norms, and its blatant intimidation of local populations."

The group warned that it will stand ready to impose "further economic costs on Russia, and on individuals and entities — inside and outside of Russia—providing political or economic support for Russia’s illegal attempts to change the status of Ukrainian territory."

“In addition, we deplore deliberate Russian escalatory steps, including the partial mobilization of reservists and irresponsible nuclear rhetoric," the group said.

-ABC News' Ben Gittleston