BERLIN — A diplomatic dispute over Turkey's EU membership bid and a crackdown on demonstrations in the country intensified Friday as Germany summoned the Turkish ambassador over comments made by a minister about Chancellor Angela Merkel.

Merkel on Monday criticized the crackdown by security forces as "much too strong." The chancellor also has long been skeptical of Turkey's ambitions to join the European Union; her coalition government supports continuing membership talks, but this week blocked a decision to move forward the negotiations.

Turkey's minister in charge of EU affairs, Egemen Bagis, suggested on Thursday that Merkel was picking on Turkey for political gain as she attempts to win a third term in September elections.

Bagis said that if Merkel is looking for "internal political material," then "this should not be Turkey." He also pointed to the election defeat last year of then-French President Nicolas Sarkozy, a fellow opponent of Turkey's EU membership.

"If Mrs. Merkel follows and reviews what happened to Sarkozy, who previously tried to use (Turkey) as political material, she will see that the fate of those who mess around with Turkey is not all that good," said Bagis, who is Turkey's chief EU negotiator.

German Foreign Ministry spokesman Andreas Peschke told reporters that ambassador Huseyin Avni Karslioglu was summoned to the ministry Friday.

He would say only that the reason was comments by a Turkish official regarding Germany and the future of the EU membership talks, adding: "These are comments that met with incomprehension — this is not in order."

In an apparent tit-for-tat action, Turkish Foreign Minister Ahmet Davutoglu said Germany's top diplomat was being summoned, because the government wanted to express its "discomfort" with what he called "certain statements that have disturbed Turkey." Davutoglu, who spoke to Turkish state media during a visit to Ukraine, did not specify what statements he meant.

Bagis said Friday he hoped that Germany "steps back from (the) serious mistake" of blocking progress in Turkey's membership talks.

Last month, German Foreign Minister Guido Westerwelle said he was hopeful of opening negotiations on another chapter in the membership talks before the end of June. But on Thursday, Germany and the Netherlands blocked a decision to do so.

That chapter concerns regional policies, not Turkey's protests. Asked whether the decision to block its opening was linked to the Turkish crackdown, Peschke said it was down to "open technical questions" on which he wouldn't elaborate.

However, he added that "of course, as always in life, everything is linked to everything else."

Human rights groups have said the protests in Turkey have left more than 5,000 people injured and more than 3,000 were detained and then released.

The demonstrations were sparked by a police crackdown on environmental activists in Istanbul May 31, but protesters also criticized what some regard as Prime Minister Recep Tayyip Erdogan's authoritarian style of leadership.

Merkel also said Monday that "what is happening at the moment in Turkey does not correspond to our idea of the freedom to protest and the freedom of speech."

NATO member Turkey began EU accession negotiations in 2005, but has made little progress, in part reflecting unease among some in Europe to admitting a populous Muslim nation.

Turkey's entry talks cover 35 different areas, or chapters. Only 13 have been opened, and several areas have been frozen over Turkey's refusal to allow ships and planes from Cyprus, an EU member, to enter its ports and airspace.

Germany itself is a potential obstacle to Turkish EU membership given that Merkel and her conservative party have long advocated a lesser, vaguely defined "privileged partnership," though Westerwelle's Free Democrats — her junior coalition partners— are less skeptical.

A spokesman for Merkel stressed that Germany's support for continuing membership talks remains unchanged.

"Neither the chancellor nor the government are in any way questioning the accession process," Georg Streiter said. "It's not about whether, only about how the accession process is continued."