DONETSK, Ukraine — Armed pro-Russian rebels in eastern Ukraine said Friday they were not bound by an international deal ordering them to disarm and were looking for more assurances about their security before leaving the public buildings they have occupied since early April.

The agreement, brokered by the United States, Russia, Ukraine and the European Union in Geneva on Thursday, offered the best hope to date of defusing a crisis in Ukraine that has dragged East-West relations to their lowest level since the Cold War, as the situation in eastern Ukrainian cities such as Donetsk grew more tense.

"We do not listen to the Kyiv government," said Alexsander, spokesman for the self-proclaimed People's Republic of Donetsk, who did not give his last name out of fear for his safety.

"They came to power as a result of the military coup, and we can act on our own," he said.

Russian Foreign Minister Sergei Lavrov "did not sign anything for us. He signed on behalf of the Russian Federation," Denis Pushilin, the leader of the separatist group, told journalists in Donetsk.

Alexsander said the group is planning on conducting a referendum by May 11 in which people can decide whether Donetsk should be an independent state, and possibly join Russia, or remain part of Ukraine.

Meanwhile, the Ukrainian government said it was preparing a law to give the rebels amnesty, although the drive to root them out would continue.

The agreement requires all illegal armed groups to disarm and end the occupation of public buildings, streets and squares. But with rebels staying put in the east and Ukrainian nationalist protesters showing no sign of leaving their unarmed camps in Kyiv’s Independence Square, it was not clear which side would be willing to move first.

Enacting the agreement on the ground will be difficult because of the deep mistrust between the pro-Russian groups and the Western-backed government in Kyiv — mistrust that this week erupted into violent clashes that killed several people.