Prime Minister Recep Tayyip Erdogan is to return to Turkey from a foreign tour as mass protests against his government's policies continue, BBC News reported.

Demonstrators have been rallying in Istanbul, Ankara and other cities for a week, with many calling for the three-term prime minister to quit.

A police officer died on Thursday, June 6 after falling off a bridge in Adana province the previous day, reports said. Three other people have been killed and thousands injured in the unrest.

The protests mushroomed after police cracked down on activists defending an Istanbul park from developers.

Erdogan has called the protests undemocratic but his deputy apologised for police violence and met representatives of the protesters from Istanbul's Taksim Square.

In the Black Sea port of Rize, a large crowd of government supporters attacked a smaller group of young people who were holding a protest on Wednesday. Police had to step in to protect them.

It appears to be the first clash between rival groups since the unrest began.