* EU calls for stronger oversight of police after protests
* EU executive backs plans to open new chapter talks
By Adrian Croft
BRUSSELS, Oct 16 (Reuters) - The European Union accused Turkish police on Wednesday of using excessive force to quell protests earlier this year, urging the government to strengthen oversight of the police and to press ahead with investigations into their conduct.
The criticism was contained in an annual report by the EU's executive Commission into Turkey's progress in meeting the requirements to join the 28-nation bloc.
Turkey began negotiations to join the EU in 2005, 18 years after applying. But a series of political obstacles, notably over Cyprus and resistance to Turkish membership in key members Germany and France, have slowed progress to a snail's pace.
Despite criticism of Ankara's handling of the protests, the Commission backed plans to breathe new life into Turkey's EU bid by opening talks on a new chapter, or policy area, of the membership negotiations, the first to be opened in three years.
EU governments, led by Berlin, postponed plans to open the talks on regional policy in June as a rebuke for the Turkish authorities' handling of the demonstrations.
Protests against the government of Prime Minister Tayyip Erdogan swept Turkish cities after police used teargas and water cannon to disperse a sit-in against the redevelopment of an Istanbul park.
Two weeks of clashes with police left four people dead and about 7,500 injured.
"The excessive use of force by police and the overall absence of dialogue during the protests in May/June have raised serious concerns," the European Commission said.
"This underlines the urgent need for further reforms and the promotion of dialogue across the political spectrum, and in society more broadly, as well as for respect of fundamental rights in practice," it said.
The Commission said Turkey had launched a number of investigations into police conduct during the protests.
"These should be followed through in accordance with European standards and those responsible brought to account," it said.
It urged Turkey to push ahead with plans to set up a monitoring mechanism to ensure the independent supervision of police conduct.
Despite the criticisms, the Commission praised judicial reforms in Turkey and Erdogan's announcement last month of a package of reforms designed to salvage a peace process with Kurdish insurgents.
There was no immediate reaction from Turkey.
Turkey's EU Affairs Minister Egemen Bagis had complained on Twitter at the weekend about the EU publishing the report during the Muslim Eid al Adha festival, which began on Monday afternoon and lasts all week.
His press adviser confirmed to Reuters on Wednesday that the government would not issue a response until after the holiday.
Turkey is deeply frustrated at what it sees as humiliating treatment by Europe, which has turned public opinion in the country against EU membership.
EU governments will consider the Commission's report at a meeting on Oct. 22 and EU sources said they could decide to launch the new round of talks with Turkey in early November.
While Turkey's membership bid has languished, Brussels has moved faster to integrate the countries of the former Yugoslavia. Croatia, which began negotiations on the same day as Turkey, has already joined the bloc and Serbia won a green light in June to start negotiations by next January.
The Commission proposed on Wednesday that EU governments formally recognise Albania as a candidate for membership.