The Ukrainian city of Donetsk was rocked by blasts on Saturday, even as government forces and pro-Russian separatists prepared to create a buffer zone to separate the warring sides.
A memorandum signed early on Saturday calls for the withdrawal of heavy weapons, including artillery, and all foreign fighters from a 30 kilometer-wide buffer zone.
A Reuters correspondent in Donetsk, the main industrial hub in Ukraine's turbulent east, said several powerful explosions were heard in the morning. A plant producing munitions and industrial explosives had been hit, municipal authorities said.
Explosions were also heard from the direction of the main international airport which government forces are still clinging on to despite rebels' attempts to loosen their control.
A nine-point memorandum was signed earlier in the day in the Belarussian capital of Minsk by the separatists and envoys from Moscow and Kiev.
"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 journalists.
The Minsk deal, which was also supported by the Organization for Security and Cooperation in Europe (OSCE), is an attempt to build on a Sept. 5 ceasefire agreement which has been regularly violated.
One Ukrainian soldier was killed and seven others were wounded in overnight violence, a military official told journalists.
President Petro Poroshenko reluctantly agreed to the cease-fire, in a conflict that has killed more than 3,000 people, after Ukrainian forces suffered reverses on the battlefield that saw them lose a southern swathe of the Donetsk region along the border with Russia.
Kiev says Russian help involving more than 1,000 Russian troops proved the tipping point, though Moscow has denied any direct role in eastern Ukraine despite what Kiev and Western government say is undeniable proof.
A humanitarian convoy of about 250 trucks from Russia arrived on the outskirts of Donetsk, though Ukrainian officials said they had crossed from Russia without authorization and in violation of international law.
Two of the drivers said the convoy had brought in a 2,000-tonne cargo of aid including flour, tinned meat and fish, and power generators.
