Turkish Prime Minister Recep Tayyip Erdogan on Tuesday claimed victory over anti-government protesters after a heavy crackdown, as police raided homes and arrested dozens of demonstrators in a bid to stamp out nearly three weeks of unrest.

After a weekend of clashes sparked by the eviction of protesters from Istanbul's Gezi Park, the focal point of the protests, demonstrators have struggled to regroup and police have since fought only sporadic battles with smaller groups of demonstrators across the country.

Senior leaders of the Palestinian Islamist movement Hamas will meet on Tuesday in Ankara with Turkish Prime Minister Recep Tayyip Erdogan, a diplomatic source told Agence France Presse.

The group's exiled leader Khaled Meshaal, along with Gaza's prime minister Ismail Haniya, will discuss Erdogan's planned visit to the Gaza Strip as well as the situation in Syria, the source said on condition of anonymity.

Turkish police detained dozens of people at their homes and raided two media offices on Tuesday in a coordinated operation across the country to clamp down on nearly three weeks of mass anti-government unrest, lawyers and local reports said.

Officers raided the homes of around 90 members of the Socialist Party of the Oppressed (ESP), a small leftist group that has been active in Istanbul's Gezi Park protest at the center of the nationwide protest movement, the Istanbul bar association said.

Ankara on Monday summoned Britain's charge d'affaires to demand an explanation over newspaper allegations that Britain spied on the Turkish finance minister's emails and phone calls during a G20 meeting in London in 2009, a foreign ministry diplomat told Agence Francr Presse.

In the absence of the ambassador, the ministry summoned the charge d'affaires "to express our concerns over the allegations", the diplomat said on condition of anonymity, adding that Ankara was expecting an "official and satisfying explanation" from British authorities.

German Chancellor Angela Merkel said Monday that she was shocked by Turkey's violent crackdown on protests in major cities, saying it "was much too harsh".

"There were horrible images in which one could see that the approach was much too harsh in my view," Merkel told commercial broadcaster RTL in reaction to news coverage of riot police breaking up demonstrations in Istanbul and the capital Ankara.

Two of Turkey's main trade unions began a nationwide strike Monday to protest at police violence against anti-government demonstrators, a day after Prime Minister Recep Tayyip Erdogan defended his crackdown on an Istanbul protest park.

Turkish Interior Minister Muammer Guler condemned the stoppage as "illegal" and warned strikers not to take to the streets, as the Islamic-rooted government battled to clamp down on nearly three weeks of nationwide civil unrest.

Germany on Sunday urged Turkey to "respect the freedom to demonstrate and freedom of expression," saying that Ankara was sending the wrong signal by cracking down on protesters.

"The German government has warned several times: freedom to demonstrate and freedom of expression must be guaranteed and peaceful citizens respected," government spokesman Steffen Seibert said in a tweet, reacting to the latest violence in Turkey.

Two of Turkey's main trade union federations, KESK and DISK, will go on strike Monday in protest at a police crackdown on anti-government demonstrators in Istanbul overnight, a spokesman for KESK told Agence France Presse.

"We are going on strike tomorrow across the country, with DISK and other vocational organizations," Baki Cinar said.

Turkish Prime Minister Recep Tayyip Erdogan on Sunday told a crowd of more than 100,000 supporters it was his "duty" to order a crackdown on an Istanbul protest park, as police and anti-government demonstrators faced off in fresh clashes.

A day after riot police dislodged thousands of protesters occupying Gezi Park, officers in the area were still firing tear gas and jets of water at pockets of protesters determined to regroup.

Police sealed off a flashpoint Istanbul park on Sunday after firing tear gas and water cannon to dislodge thousands of protesters in a night of violence that sent tensions soaring in Turkey following more than two weeks of anti-government unrest.

Riot police were still clashing with pockets of protesters in streets near Gezi Park as tens of thousands of supporters of Prime Minister Recep Tayyip Erdogan began gathering for a rally 10 kilometers (six miles) away.