Ukrainian officials and pro-Russian separatists agreed to a cease-fire on Monday after a failed attempt on Friday. The talks between the officials and separatist leaders were the first held since the start of the Ukrainian crisis.

Although Ukrainian President Petro Poroshenko announced a cease-fire on Friday, pro-Russia separatists continued to attack the cities of Donetsk and Luhansk. On Monday, representatives from the Ukrainian government met face-to-face with rebel leaders and both sides agreed to a cease-fire, the Wall Street Journal reported.

The cease-fire agreement failed at first because the separatists never agreed to it, but after Monday's talks, there was optimism the cease-fire would continue until at least Friday.

A partnership between Russia and the Organization for Security and Cooperation in Europe will ensure that the cease-fire is monitored, said Alexander Borodai, leader of the so-called Donetsk People's Republic, according to the Wall Street Journal.

According to another separatist leader, Pavel Gubarev, the original agreement on Friday was “just fake."

"Ukrainian forces are either not under [Poroshenko's] control, or he is just a liar," Gubarev said, according to the Associated Press.

Despite a number of U.S. sanctions against separatists and current restrictions imposed on Russia, the Ukrainian crisis has led to more than 350 deaths so far.