“If there is a decision to use force to clear the protesters, it can be done but will start a civil war,” said Ihor Smeshko, former head of Ukraine’s SBU security services. “The army is so far neutral, but if it is pulled into this conflict it will be a point of no return. Army personnel are themselves split 50/50 in their views of Ukraine.”

The government prepared the way for using the army on Wednesday, when the defence ministry said the military could be deployed in “antiterrorist” operations. Authorities and legal experts had previously said the army could only be used within Ukraine if a state of emergency was imposed.

Mr Yanukovich on Wednesday night also replaced the head of all Ukraine’s armed forces with the former navy chief – just weeks after he already replaced the head of the army – in what appeared to be a move to ensure loyalty in the top ranks.

In Washington, those moves generated particular alarm. “We urge the Ukrainian military not to get involved in a conflict that can and should be resolved by political means,” said Jay Carney, a White House spokesman.

A state department official noted efforts were under way to lobby Ukraine’s top brass. “In the past, we have been able to make direct contact with senior military and intelligence officials in the Ukrainian government,” the official said. “It is worrying to us that has been difficult over the last 24 hours.”

The fact the Ukrainian authorities were contemplating using the military emphasised Mr Yanukovich’s relative shortage of resources for crushing the protests. It also raised questions about how much of the army, despite the leadership changes, would obey orders to use force against their own people. . . .

“The core of the army does not support Yanukovich and will not execute an order” to use arms against ordinary people, Mr [Director of Center for Army Conversion and Disarmament Studies Valentyn] Badrak said. “This will be an illegal order and will mean for the army that it is being pulled into illegal action.”

Ukraine’s armed forces have had extensive contacts with Nato troops in recent years, as a member of Nato’s Partnership for Peace programme, with officers receiving Nato training.

“Don’t underestimate the strength of the army’s own professional ethos, part of which is that they don’t get engaged in this type of action” against ordinary citizens, said Mr [Chatham House scholar James] Sherr. “Their training, the respect of the officers for the constitution, and 20 years of close working with Nato countries, that affects the whole mentality.”

Image: Violence in Kiev, Jan.19, 2014 (photo: Mstyslav Chernov)