Ukraine crisis: Details of Poroshenko's peace plan emerge
Details have emerged of a 14-point peace plan to be unveiled by Ukraine's President Poroshenko later.
The document, calling for disarmament in eastern Ukraine, appeared in Ukrainian media overnight.
It comes after Mr Poroshenko held his second phone conversation this week with Russia's President Vladimir Putin.
Heavy fighting is continuing between government forces and pro-Russia rebels, with new reports of military hardware entering Ukraine from Russia.
Ukrainian Defence Minister Mykhaylo Koval told parliament on Friday that Ukraine had closed its border to military vehicles in the past week, but that three tanks and 10 Grad rocket launchers had already crossed over.
"We are keeping an eye on these vehicles, watching them," he said. "As soon as they appear within artillery range, we open fire immediately."
Meanwhile Dmitriy Peskov, a spokesman for Mr Putin, said the president had ordered measures to be taken to "strengthen the protection of Russian borders".
But he dismissed remarks by Nato Secretary-General Anders Fogh Rasmussen that at least a few thousand Russian soldiers had been deployed to the border area, saying "there is no build-up".
In their telephone conversation on Thursday night, the Ukrainian and Russian presidents discussed Mr Poroshenko's proposals for a peace plan , which is due to be presented officially on Friday.
The document promises to decentralise power and hold early local and parliamentary elections.
It also proposes the creation of a 10km (6 mile) buffer zone on the Ukrainian-Russian border, and a safe corridor for pro-Russian separatists to leave the conflict areas.
Mr Poroshenko has already announced that he intends to introduce a unilateral ceasefire by government forces ahead of the peace plan being implemented.
Analysis: David Stern, BBC News, Kiev
Many of the details of President Poroshenko's peace proposal are already known: a unilateral ceasefire, peace talks, increased autonomy to the regions, protection for the Russian language. What is unclear is how he intends to implement it, and what the reaction from the other side will be.
Even if he calls a truce, the pro-Russian insurgents seem to have no intention of laying down their arms, or even observing the ceasefire at all.
Russia likewise is sending highly mixed signals. President Putin has reacted favourably to Mr Poroshenko's proposal, and the two men are in communication.
But Ukrainian and Western officials say Moscow has resumed its troop build-up on the border. And Russian fighters, and possibly heavy military hardware, are crossing into Ukraine.
Mr Poroshenko obviously is aware of all these realities. What remains to be seen is what he plans to do if the peace plan fails.
Earlier this week, Mr Poroshenko said a "brief" truce - expected within days - would allow militants in Donetsk and the neighbouring Luhansk region to lay down their arms.
Rebels rejected the call to surrender their weapons.
Meanwhile 12 Ukrainian soldiers were killed and 25 were injured in continued fighting near the town of Krasny Liman, in the Donetsk region, on Thursday evening, Interfax-Ukraine news agency quoted defence officials as saying.
Government forces said about 300 separatists had been killed in the violence, but this figure has not been independently confirmed.
A limited truce has been observed in Luhansk where rebels and government forces have been exchanging the bodies of their dead.
Summary: Ukraine peace plan
- Disarmament with a guarantee that those who have laid down arms and have not committed any "serious crime" will not face criminal prosecution
- Measures to decentralise power and early local and parliamentary elections
- Illegally occupied buildings to be vacated and hostages to be released
- A 10-km buffer zone on the Ukrainian-Russian border and safe corridor for separatists to leave by
- Central TV and radio broadcasting to resume in Donetsk and Luhansk regions
When discussing the peace plan with Mr Poroshenko, Mr Putin expressed hope that priority would be given to "resolving key problems that have caused strong protests by the people" in eastern Ukraine, the Kremlin said in a statement.
The unrest comes amid tension between Russia and Ukraine over the removal of pro-Moscow President Viktor Yanukovych and Russia's annexation of Crimea.
Mr Poroshenko said on Thursday he would sign a controversial association agreement with the EU on 27 June.
Mr Yanukovych was overthrown in February after refusing to sign the deal at the last moment.