Ukraine crisis: Second OSCE team freed in Donetsk
Pro-Russian rebels in eastern Ukraine have released the four remaining European monitors they were holding.
The Organization for the Security and Co-operation in Europe observers were detained last month. Another OSCE team was released earlier this week.
The move comes amid a shaky ceasefire between government forces and rebels.
President Petro Poroshenko extended the week-long truce on Friday for three days, but fresh clashes have put it under increasing strain.'A path of peace'
In all, two observer teams - a total of eight international monitors - were detained by gunmen in eastern Ukraine last month.
Four monitors - kidnapped in the Donetsk region on 26 May - were freed in the early hours on Friday.
Negotiations for the release of the other group, who were taken on 29 May in Luhansk, had intensified in recent days.
Footage on a Russian TV news channel showed the three men and a woman shaking hands with OSCE representatives and entering a hotel in Donetsk city.
In a statement, OSCE chairman Didier Burkhalter said he was relieved to hear of the group's release and said the OSCE was ready to help implement President Poroshenko's peace plan.
OSCE spokesman Michael Bociurkiw said: "They're in good health, they're in good spirits."
The release of all observers had been a key demand made by the EU in its policy statement on Ukraine on Friday.
Insurgent leader Alexander Borodai said: "We have fulfilled our obligations."
Russian President Vladimir Putin had publicly called for the release of all hostages under the terms of the temporary ceasefire.
He had also called for a long-term truce to allow for further negotiations, urging Mr Poroshenko to embark on a "path of peace".
The ceasefire came under increasing strain on Saturday amid reports of fresh clashes between government forces and rebels in the east.
Ukrainian military sources said at least one soldier had been killed near the rebel stronghold of Sloviansk.
Some rebel leaders have said they will observe the truce but others oppose it.
The Unian news agency quoted a Ukrainian National Security and Defence Council spokesman as saying the government reserved the right to cancel the truce if the breaches continued.
But it also quoted Defence Minister Mykhailo Koval as saying: "Everyone knows that a bad peace is better than a good war."'Drastic measures'
Mr Poroshenko set out a 15-point peace plan on 20 June. It involves decentralising power and holding early local and parliamentary elections.
It also proposes the creation of a 10km (six-mile) buffer zone on the Ukrainian-Russian border, and a safe corridor for pro-Russian separatists to leave the conflict areas.
German Chancellor Angela Merkel warned Russia on Friday the EU was prepared for "drastic measures" if there was no speedy progress on the plan.
Mr Poroshenko on Friday signed a landmark EU trade pact - the issue that has been the trigger of the recent crisis.
The refusal of Mr Poroshenko's predecessor, Viktor Yanukovych, to sign the EU deal - under pressure from Russia - led to protests in Kiev and his eventual overthrow this year.
Russia then annexed Ukraine's Crimea region, and separatists in the east declared independence from Ukraine.
More than 420 people have been killed in fighting between pro-Russia rebels and government forces in eastern Ukraine since mid-April, the UN estimates.