ISTANBUL (AFP) - 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 centre of the nationwide protest movement, the Istanbul bar association said.

Police also searched the offices of the Atilim daily and the Etkin news agency, local media outlets linked to the ESP group, the NTV and CNN-urk television stations reported.

NTV said 30 people were arrested in the capital Ankara and another 13 in the north-western city of Eskisehir in a police swoop targeting 21 provinces overall.

Under Turkish law, the detainees may be questioned for four days before
they are taken to court to be freed or charged.

Turkey has taken a tough stance against the tens of thousands of demonstrators who have been protesting since May 31 against Prime Minister Recep Tayyip Erdogan's Islamic-rooted government, seen as increasingly authoritarian.

Police have used tear gas, water cannon and rubber bullets to quell the demonstrations, leaving thousands injured and four dead.

Tensions soared on Saturday when police stormed the flashpoint Gezi Park to evict protesters, triggering a weekend of heavy clashes.

Demonstrators have since struggled to regroup and the protests appeared to have lost some of their momentum with only sporadic clashes reported.