Germany is seeking to delay EU membership talks with Turkey scheduled for this month, in response to Ankara's crackdown on mass demonstrations that have shaken the government of Recep Tayyip Erdogan.
The prospect that the negotiations – a potential turning point in the long and troubled relationship between Ankara and the bloc – could be put on hold came as the Turkish prime minister delivered a "final warning" to protesters that they were no longer safe to remain in Istanbul's Gezi Park, epicentre of the demonstrations.
"It is not exactly a good moment to be giving Erdogan any reward," said a senior German diplomat.
Berlin, together with other EU states and the US, has called on Mr Erdogan to respect the protesters' freedom of expression. Mr Erdogan met protesters late on Thursday but earlier declared his patience at an end, urging a plebiscite to resolve the future of Gezi Park itself.
Ankara's membership prospects have long been clouded by the opposition of Angela Merkel, German chancellor, and other EU leaders. But both Ankara and the EU argue that kick-starting the stalled negotiations is important in improving relations between Turkey and the bloc, and bringing the country closer to EU standards.
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The talks, scheduled for June 26, were to be the first opening of a negotiating "chapter" for three years – and hence have assumed considerable symbolic importance. But they can be vetoed by any EU member state.
Several diplomats said Berlin was lobbying to persuade other EU states to halt the talks, in one of the first concrete signs of an international backlash to Ankara's tough stance on the protests. One said that "consensus was forming" to delay the talks, focusing on regional policy, while another said France, Italy, Sweden and Finland were also leaning towards halting the negotiations.
Some EU diplomats said Berlin was seeking to avoid provoking Mr Erdogan by depicting the delay as technical in nature and based on formal conditions for the talks to begin.
A German foreign ministry spokesman said: "There is some doubt whether these questions can be cleared up in time for negotiations on the chapter to start" before the end of the Irish EU presidency at the end of this month.
But Ankara is already upset at what it regards as a "disproportionate" response to the events in Gezi Park and elsewhere.
"I can't understand why the Germans are behaving like this . . . It is going to be really hard to start again if this happens," said one Turkish official. "We won't be knocking on their door for a long time after this . . . Things are hardening on both sides."
In a two-hour speech in Ankara, Mr Erdogan linked the protests to the "insatiable" financial sector, criticised the international media for its coverage, and said he would give details on Friday of a plot against Turkey. The Turkish newspaper Milliyet reported that Mehmet Muezzinoglu, Mr Erdogan's health minister, had warned that volunteer medics in Gezi park, who have treated scores of wounded people, would be investigated.
In Gezi Park itself, protesters steeled themselves for an imminent police operation to clear the area. Many wore hard hats to protect against tear gas canisters, which have caused a number of serious head injuries.
"I am afraid, actually," said Ayse, who works in logistics. "The tear gas hurts but we are going to stay; and if we are pushed out we will come back."
(Read More: Turkey Enters New 'Phase' After Police Action)
Despite explicit warnings from Mr Erdogan for parents to remove their children from the park, many Turks still came with their families to the area.
"We came to see because we are curious," said Emrah, a factory worker with two children under five, as he entered the park from the neighbouring Taksim Square. "We are citizens of this country."