“Signal” that the US is ready to use its air power to support a European security force in Ukraine was given by Donald Trump on Tuesday but he ruled out sending US ground forces.

As reported by the Wall Street Journal, after the Trump-Putin summit in Alaska, the US president tasked US Air Force chief Dan Kaine to draw up a plan with options for “NATO-style” security guarantees for that force, according to a Western official.

According to the report, the US Pentagon could deploy aircraft outside Ukraine to protect European troops, including fighter jets to assist European forces in the country in the event of an attack or surveillance drones to monitor any peace agreement.

The US could also transport European troops and equipment in its transport aircraft, provide ground air defense systems to European forces and contribute military intelligence.

However, this plan, WSJ notes, faces a number of significant diplomatic challenges as Russia has opposed the idea of NATO members sending troops to Ukraine.

“We reiterate our position, which we have repeatedly expressed, that we reject any scenario that envisages sending a military body to Ukraine with the participation of NATO states,” Russian Foreign Ministry spokeswoman Maria Zakharova said Tuesday. Such a move, she said, could lead to an “uncontrolled escalation of the conflict with unpredictable consequences.”

European governments, led by the United Kingdom and France, have for months been pressuring Washington to support what they describe as an “reassurance force” to be deployed in Ukraine after the cease-fire. European countries are wary of sending troops to Ukraine without what the British call U.S. “support”
that is, assurance that U.S. forces will be able to intervene in the event of an attack on the troops.

An indication of NATO members’ concern about possible military moves by Moscow, however, was the North Atlantic alliance’s announcement yesterday, Tuesday, that its military forces, including air defence systems, were put on alert when Russian aircraft launched missile attacks against Ukraine.