The United States on Thursday welcomed plans for talks between Ukrainian President Viktor Yanukovych and opposition leaders after five days of deadly clashes between protesters and security forces.

Washington also said it was still looking at whether to impose sanctions on the Ukrainian government over the violence -- which it says is the result of a refusal to take the grievances of the protesters seriously.

"We are deeply concerned by the violence," White House spokesman Jay Carney said.

"We welcome the news that President Yanukovych is meeting directly with opposition leaders.

"Political dialogue to address the legitimate concerns of the Ukrainian people is the necessary first step towards resolving this crisis."

Activists say five protesters have died in clashes in recent days, marking a new peak in tensions after two months of protests over the government's failure to sign a deal for closer integration with the European Union.