President Barack Obama spoke Saturday with the leaders of Ukraine and Germany as fighting continued between Ukrainian forces and Russian-backed separatists in eastern Ukraine hours before a scheduled cease-fire.

The White House says Obama and Ukrainian President Petro Poroshenko stressed the need for all sides to halt the violence beginning at midnight in the region as scheduled.

The leaders of Germany, France, Ukraine and Russia agreed to the cease-fire this week after a marathon negotiating session in Belarus.

The White House says Obama, Poroshenko and German Chancellor Angela Merkel all expressed concern over intense fighting in and around the key government-held railway hub of Debaltseve.

Obama spoke with the leaders from aboard Air Force One as it flew him to the Palm Springs area of Southern California for a weekend vacation.

He also congratulated Poroshenko on securing International Monetary Fund assistance to help stabilize the Ukrainian economy.

(AP)