Clashes continued in eastern Ukraine Saturday despite a newly signed memorandum of understanding and an earlier cease-fire agreement. A munitions and industrial explosives factory was hit Saturday when several strong blasts rocked Donetsk, Reuters reported. A Russian aid convoy of 250 vehicles also arrived at the border in what Ukrainian officials are calling a violation of international law.

Kiev and Moscow signed a nine-point memo Saturday that would create a buffer zone between government forces and pro-Russian separatists, while requiring both sides to remove their heavy artillery. Foreign fighters also would have to leave the buffer zone, which would be about 18.6 miles wide, the Associated Press reported.

The deal was signed after a night of clashes that left one Ukrainian soldier dead and several others wounded. After agreement on the buffer zone was reached, explosions were heard near Donetsk’s main international airport, Reuters said. Government forces are still in control of the airport.

“According to the text of the memorandum, each of the sides must pull back its heavy equipment and arms from today,” Volodymyr Polyovy, an official of Ukraine's national security and defense council, told reporters Saturday. The memo builds on the cease-fire agreement reached between Ukraine and pro-Russian rebels Sept. 5, Reuters said.

More than 3,000 people have died since the beginning of the conflict between Ukraine and pro-Russian separatists, mostly in the eastern reaches of the country. Ukraine and the West have largely blamed Russia for fueling the conflict with weapons, fighters and funds. Russia has denied involvement.