Turkish riot police fired tear gas and water cannon to block demonstrators from entering Gezi Park in Istanbul, the birthplace of unrest that engulfed the country last month.

The police move came after protesters started to gather in Taksim Square to enter Gezi Park which was reopened to public by Turkish authorities earlier in the day but closed again shortly on Monday.

Clashes between police and protesters continued late into the evening in the Taksim area, as a spokesman for Taksim Solidarity Platform, the umbrella group of the protesters, told a news conference police detained more than 80 people.

Al Jazeera's Serpil Karacan, reporting from Istanbul, said that after The Taksim Solidarity Platform called to gather at the area, police cleared people from the park and prevented others from entering.

Istanbul Governor Hüseyin Avni Mutlu announced the opening of the park earlier in the day, warning those who defy laws and state officials will face harsh response. "Gezi Park won't be occupied again, isn't the place for demonstrations, march without permit is illegal," he said.

The governor also said there'll be a fast-breaking event during Islam’s holy month of Ramadan every evening at the park.

The opening was scheduled for Sunday but had been pushed back to Monday due to tension and protests over the weekend. Police fired teargas and water cannon to disperse hundreds of protesters at Taksim Square in Istanbul on Saturday evening as they gathered to enter Gezi Park.

Gezi park has been closed for three weeks since a police intervention forced protesters out of the site on June 15 where they had stayed for nearly two weeks before the operation.

The crisis began when a sit-in to save Gezi's 600 trees from being razed in a redevelopment project prompted a brutal police response on May 31, escalating into countrywide demonstrations against Erdogan, seen as increasingly authoritarian.

Four people have been killed and nearly 7,500 people injured, according to the Turkish Medical Association.