Seven military observers, including four Germans, from the Organization for Security and Cooperation in Europe (OSCE) were captured last Friday in eastern Ukraine and held for more than a week by pro-Russian separatists.
On Sunday the deputy leader of Chancellor Angela Merkel’s Bavarian allies, the Christian Social Union (CSU), questioned why Germany had sent its military observers on the Ukraine mission.
“I can see that it is in the interest of the revolutionary government in Kiev, whose legitimacy one has reasons to doubt, to 'invite' German soldiers into the conflict zone, but I don't understand how it can be in our interest to allow ourselves to be dragged further into the conflict in such a clumsy manner,” Peter Gauweiler told Spiegel.
There was also criticism from Merkel’s centre-left coalition partners, the Social Democrats (SPD). Their defence spokesman Lars Klingbeil called for a report into the mission by the defence ministry.
And the defence committee chairman of the opposition party Die Linke, Alexander Neu, said the government was yet to give a plausible explanation why unarmed German soldiers were in the crisis zone. He described the mission as a “serious political mistake”.
But defence minister Ursula von der Leyen, who greeted the freed German hostages in Berlin on Saturday night defended the operation.
However, she told broadcaster ZDF on Sunday evening that it would be “analyzed again”.
'Happiness and relief'
The head of the OSCE team released by pro-Russian rebels expressed his "deep relief" after an ordeal that lasted more than a week.
"It is happiness, a deep relief," German Colonel Axel Schneider told a small group of journalists on the road outside of the Ukrainian city of Donetsk.
He spoke as he and the rest of the freed members of the OSCE team were on their way to Donetsk, from where they flew to Kiev and then onwards to Berlin in a German government jet, where they landed late on Saturday night.
Visibly moved on his return to the German capital, Colonel Schneider told journalists: "Imagine, last night we were in the midst of gunfire, tonight we are with our families. We would never have thought it possible."
Von der Leyen, said she was "filled with relief" that the OSCE team had "landed unharmed and healthy".
The group, all men, consisted of seven Europeans - four Germans including Schneider, one Pole, one Dane and one Czech - as well as five Ukrainian military officers who had been accompanying them.
They were seized by pro-Russian rebels on April 25th and kept in Slavyansk, where the insurgents at one point made them give a news conference under armed guard. One inspector, a Swede, was released on April 27th because he suffered from diabetes.
The rebels insisted that the prisoners - whom they called "guests" - would only be exchanged for militants taken prisoner by Ukrainian authorities.
The observers spent the first hours of their captivity in a basement with their hands tied and eyes blindfolded, the Czech observer, Lieutenant Colonel Josef Prerovsky, told Czech television in Donetsk. "Those first eight hours were the worst," he said.
"We spent the first two days in a basement constantly under guard, accompanied even when we went to the bathroom," he said. "Then they untied our hands and allowed us to move in the basement."
The atmosphere became more tense on Friday, when the Ukrainian military launched an offensive on Slavyansk, with one of the aims to force the rebels to free the OSCE team.
"It was really tough the last two nights as we saw the situation developing then. Every minute gets longer," Schneider said. In the end, after days of outrage from Western capitals over their captivity, direct intervention from a Kremlin envoy, Vladimir Lukin, resulted in their liberation.
Lukin later told a news conference in Donetsk that the pro-Russian rebels' decision "was motivated by humanitarian concerns".
He sought to distance himself from accusations that Russia had control over the rebels, saying: "I am a Russian citizen and am far from interfering in the internal affairs of Ukraine."