Germany hardened its stance Thursday against Turkey over its military offensive against a Kurdish militia in Syria, which threatened to end a thaw in frosty relations between the NATO partners.
Foreign Minister Sigmar Gabriel voiced "great concern" about Turkey's cross-border military incursion, called for NATO to discuss the situation and said Berlin would put on ice any weapons deals.
Most painfully for Turkey, he postponed for at least several months a request to upgrade German-made Leopard tanks which Ankara has deployed in its operation against the Syrian-Kurdish militia YPG.
Gabriel said Berlin and Paris were committed "to stopping a further escalation, to allowing humanitarian access and protecting the civilian population. That has top priority".
Germany is home to three million ethnic Turks and hundreds of thousands of Kurds, and tensions heightened by the military conflict have again spilled into the EU country.
Kurdish protesters brawled with Turkish air passengers at Hanover airport on Monday, while in the eastern city of Leipzig attackers smashed the windows of mosques run by the Turkish-controlled Ditib organisation.
'No dirty deals'
The tensions threaten to reverse progress in Berlin-Ankara ties that had only recently started to recover.
Relations had plummeted especially after Germany criticised the human rights situation in Turkey amid a mass wave of arrests following a 2016 failed coup.
Germany has been particularly angered by Turkey's arrest of several of its citizens, including dual-nationality Die Welt daily journalist Deniz Yucel, who has been held for 11 months.
But in a gradual rapprochement, Gabriel weeks ago invited to his family home his Turkish counterpart Mevlut Cavusoglu at a time Ankara was releasing several of the Germans Berlin has labelled "political hostages".
Cavusoglu in the talks presented a request -- for Berlin to allow German arms maker Rheinmetall to overhaul Turkey's fleet of Leopard 2 battle tanks with better armour and defence systems.
Berlin has delivered over 700 of the tanks to Turkey since the 1980s, including 354 Leopard 2 tanks between 2006 and 2011.
Turkey wants to upgrade them after several were reportedly destroyed with mines or explosives by Islamic State group jihadists in 2016.
News weekly Der Spiegel wrote that Germany had hoped that giving the green light to such an overhaul would aid efforts to free Yucel, although the government has denied any link.
Yucel himself said this month, in a written interview with German news agency DPA from his Turkish jail cell, that he was "not available for any dirty deals" to win his freedom.
The situation changed dramatically when battlefield images from Syria this week showed Turkey was using Leopard tanks there.
German weapons exports are a sensitive issue for many voters who believe that profiting from military conflicts is unethical.
The far-left Die Linke and Greens opposition parties quickly demanded an end to all military cooperation with Turkey.
And lawmaker Norbert Roettgen of Merkel's CDU party protested that "it is completely out of the question for Germany to increase the combat strength of the Leopard tanks in Turkey if the Turkish army is going after the Kurds in northern Syria".
Under growing domestic pressure, Gabriel put an end to the deal on Thursday, at least for now.
"Concerning the current discussions about defence exports, the government is clear about the fact that we must not and will not export into conflict zones," he said in a statement.
The topic of weapons exports would be discussed in coming weeks in talks between his Social Democrats and Merkel's conservatives on whether to renew their current right-left "grand coalition" he said.
"That is why we, as the caretaker government, agree that we will ... postpone any consultations on critical projects until the formation of a new government."