Ukrainian President Petro Poroshenko on Wednesday proposed a unilateral ceasefire by his troops to allow pro-Russian separatists in the east of the country a chance to lay down weapons or leave the country, Russian and Ukrainian news agencies reported.

Poroshenko was quoted as saying this would be the first step in the peace plan he has proposed to de-escalate the conflict. Poroshenko's spokesman was not immediately available to confirm the offer of a unilateral move.

The president was quoted as saying: "The plan will begin with my order for a unilateral ceasefire." He added that "shortly afterward the plan will receive support from the other participants."

The proposal, reportedly disclosed during a visit to an army academy in Kyiv, comes after a telephone call between Poroshenko and Russian President Vladimir Putin in which a ceasefire was discussed.

The country's defence minister, Mikhail Koval, was quoted as saying the ceasefire could begin "literally within days."

Russia's Foreign Minister Sergey Lavrov, speaking in Baku, Azerbaijan, said that any ceasefire should be "comprehensive," not temporary. However, he said that if it was followed by negotiations "then it could be the step President Poroshenko has promised and which in general we were all waiting for."

Any such ceasefire would raise the question of whether the separatists would respect it, and whether Russia had the desire or the ability to persuade them to do so.

Separatists have seized government buildings, held disputed referendums and declared independence in the Donetsk and Luhansk regions along Ukraine's eastern border with Russia. Ukrainian troops have struggled to suppress the insurgents, who on Saturday shot down a military transport plane, killing all 49 on board. Authorities say more than 300 people have died in fighting.

Willing to negotiate

Poroshenko was elected after a protest movement drove his predecessor, Viktor Yanukovych, from office in February.

In his inaugural address June 7, Poroshenko said he was willing to negotiate with people in the region, but not with "terrorists" with "blood on their hands." He proposed an amnesty for separatists who have not committed violent acts, early regional elections and new efforts to create jobs in the area.

A report issued Wednesday by UN monitors said a  steady rise in killings, torture and abductions by pro-Russia armed groups in eastern Ukraine has claimed hundreds of lives since last month.

At least 356 people, including 257 civilians, have been killed since May 7, according to the 34 monitors with the UN human rights office. Among those casualties are 86 Ukrainian military personnel, including the killing of 49 crew and troops who died when a Ukrainian military transport plane was shot down by separatists last week. The other 13 dead were not specified.

There have been more than 200 reports of torture, the new report says, and 81 people were being held on June 7 as the deadly conflict raged in eastern Ukraine between pro-Russia separatists and the government in Kyiv.

Climate of fear

"We're talking about a reign of fear, if not a reign of terror, in those pocket areas," Gianni Magazzeni, head of the rights office's European department, told reporters.

UN human rights chief Navi Pillay said in the report Wednesday that a "climate of insecurity and fear" has displaced 34,000 people, nearly half in Ukraine's eastern regions of Donetsk and Luhansk, which have declared independence from Kyiv.

"The escalation in criminal activity resulting in human rights abuses is no longer limited to targeting journalists, elected representatives, local politicians, civil servants and civil society activists," the report says.

"Abductions, detentions, acts of ill-treatment and torture, and killings by armed groups are now affecting the broader population of the two eastern regions."

Magazzeni said monitors found that many people are "so fearful for their lives that they would not even want to dare to vote if they had a chance to do so."