WASHINGTON (AP) — The Obama administration imposed sanctions Friday on several pro-Russian separatist leaders in Ukraine, including self-proclaimed rebel mayors, governors and commanders in chief of cities under siege, for refusing to cede to the central government in Kiev. The sanctions came as U.S. officials renewed accusations that Russia is providing the separatists with tanks and heavy weaponry and as Ukraine’s president announced a unilateral ceasefire that Washington urged Moscow to support.

The penalties on seven separatists were intended as a signal that the U.S. will continue to punish those it holds responsible for instability in Ukraine and that the West was still prepared to slap tougher sanctions on Russia’s economic sectors to punish it for stoking unrest in Ukraine should Moscow not take steps to de-escalate the crisis, the officials said.