As Russia ordered troops into eastern Ukraine, President Joe Biden on Tuesday announced sanctions on two major Russian financial institution along with sanctions on Russian sovereign debt.

"All bets are off," said Raymond Taras, a political science professor at Tulane University when asked if he thought an invasion could still be averted.

Taras is an expert on on Russia-Ukraine relations. He and Chris Fettweis, a professor of political science and an expert in foreign policy are available for comment on the latest developments in the crisis.

A “dirty bomb” has never been used in conflict, and Tulane University political scientist Chris Fettweis doesn’t expect one to be used in the Russia-Ukraine war.

A dirty bomb is a mix of explosives, such as dynamite, with radioactive powder or pellets. When the explosives are set off, the blast carries radioactive material into the surrounding area.

Russia has accused Ukraine of planning such an attack. But those claims have been refuted by NATO, and U.S. officials have called them “transparently false.”