WASHINGTON (AP) -- The United States says Ukrainian rebels launched more attacks over the last three days than any similar time period since February, in what may be an escalating effort by Russian-backed militants to destabilize Ukraine's Western-backed government.
State Department spokesman John Kirby says the attacks include a heavy artillery assault on a southeastern Ukraine town.
Kirby says since Saturday, three soldiers have been killed and 35 wounded in 127 distinct separatist attacks reported by Ukraine.
Kirby on Monday said the separatists and Moscow cannot "talk peace and then fight" and urged both sides to adhere to a February cease-fire agreement.
He also expressed concern about an arson attack in eastern Ukraine on four armored cars operated by a European observer mission.
Ukraine's conflict has killed some 6,400 people since April 2014.