European military observers who were held more than a week by pro-Russian separatists have arrived in Germany a day after they were released in the Ukrainian eastern town of Slovyansk.
The five observers from the Organisation for Security and Cooperation in Europe (OSCE) - along with five of their Ukrainian assistants - were freed on Saturday.
They were deployed following a pact struck between Russia, Ukraine, the European Union and the US in mid-April aimed to resolve the crisis, which began with Russia's annexation of Crimea.
"We are deeply relieved that the members of the kidnapped OSCE team have landed unharmed here in Germany, in Berlin," Ursula von der Leyen, Germany's defence minister, said in Berlin.
"I would like to express my deep gratitude and my respect for the infinitely good cooperation we saw."
Nicolai Wammen, Denmark's defence minister, said they would continue to support the OSCE mission.
"It is important that they can work and conduct their important business in Ukraine and that this event will not make that more difficult in the future," he said.
The mission's prospects became clouded a week after their deployment when they were detained by armed men in Slovyansk, the crucible of unrest in eastern Ukraine.
The pro-Russian separatists holding them alleged the observers were spying for NATO and carrying suspicious material; one from non-NATO member Sweden was released two days later, but the rest remained in custody until Saturday.
The separatists' leader in Slovyansk, Vyacheslav Ponomarev, was quoted by Interfax news agency as saying he ordered the release because of increasing insecurity in the city, according to the Associated Press news agency.
In recent days, at least four Ukrainian soldiers were killed on the city's outskirts - two of them when helicopters were shot down - and at least 10 civilians have been killed, according to Ponomarev.
Ponomarev later told the Associated Press news agency that the OSCE observers "are not being released - they are leaving us, as we promised them".
One of the released observers, German Col. Axel Schneider, told the Associated Press that the 12 detainees held up well. Those held included three other Germans and a soldier each from the Czech Republic, Denmark and Poland.
"They had a very good attitude and that gave them the strength to stand the situation," Schneider said of the observers. "According to the word of [Ponomarev], we have been treated as good as possible. This is a miserable situation, but we were under his protection."
Ponomaryov had initially told the the Interfax news agency he ordered the release because of increasing insecurity in the city as Kiev pressed ahead with a military campaign to reclaim rebel-held territory in the area.
War against separatists
Vasyl Krutov, the head of Ukraine's "anti-terrorist centre", said on Saturday that clashes in the east against pro-Russian rebels "were not just some kind of short-lived uprising, it is in fact a war".
Ukraine forces took control of areas around the town of Kramatorsk.
"We are not stopping," said the interior minister, Arsen Avakov.
Ukraine accuses Russia of backing pro-Russian groups in eastern Ukraine. Russia denies invovlement with the rebels.
Tensions have heightened sharply after at least 42 people were killed in clashes between government supporters and opponents in the worst violence since the toppling of pro-Russian Viktor Yanukovich from the presidency in February.
The violence broke out on Friday afternoon in the Black Sea port of Odessa, when the two sides confronted each other, leaving three people dead, reportedly by gunfire.
The clashes prompted government opponents to seek refuge in a building that caught fire after protesters threw firebombs.