Following the EU's decision, Monday (14 April) to expand the list of Russian officials targeted by an asset freeze and travel ban, the United States announced that it is considering supplying arms to Ukraine.
Meeting in Luxembourg, EU foreign ministers confirmed their intension to expand their targeted sanctions, without specifying who would be affected. The US announcement was made separately.
"From our point of view there is a very obvious Russian hand in all of this and we consider these actions to be destabilizing and dangerous," Thomas Shannon, an adviser to Secretary of State John Kerry said on Monday.
Ukraine's president on Monday threatened military action after pro-Russian separatists occupying government buildings in the east ignored an ultimatum to leave and another group of rebels attacked a police headquarters in the troubled region.
Asked during a trip to Berlin whether the United States could arm Ukrainian forces, Shannon said: "Obviously we are looking at that as an option ... but at this point I can't anticipate whether or not we are going to do that."
Republican Senator John McCain has suggested providing weapons to the Ukraine government, which says the occupations that began on Sunday are part of a Russian-led plan to dismember the country.
"From our point of view, what we are seeing in a series of cities mimics what we saw in Crimea both in terms of the tactics and in terms of the people involved," said Shannon, who holds the title of counselor.
It is unclear how a US decision to supply military equipment to Kyiv would be reconciled with the current strategy of sanctions. Such a threat will likely cast a shadow over the adoption of new measures, to be reviewed at an emergency summit next week, if talks involving Russia, Ukraine, the United States and the EU, in Geneva this Thursday, fail to secure any breakthroughs.
The United States already supplies Russian neighbor Georgia with military equipment, and has trained its armed forces, since 2002. The Russian government has repeatedly criticized US-Georgian military ties. While Ukrainian forces have undertaken exercises with NATO (including a March event hosted in Bulgaria), and participate in alliance-led peacekeeping missions, they have not been a recipient of Western military assistance.
Russian Foreign Minister Sergei Lavrov has dismissed Western accusations that Moscow is destabilizing Ukraine, saying the situation could improve only if Kyiv took into account the interests of Russian-speaking regions.