Palestinians confronts Israeli police officers at a gate of Aqsa Mosque in Jerusalem’s Old City.

Israel deployed hundreds of extra police around the Old City of Jerusalem on Friday after Palestinian leaders called for a ‘day of rage’ to protest at new Israeli security measures and the U.N. calling for restraint and calm.

Around 800 extra police were posted in the heart of the city and adjacent Arab neighborhoods, where tensions have been high for the past week, following violent clashes at al-Aqsa Mosque and stone-throwing attacks by Palestinians against Israeli cars.

The focus of tension is the compound housing al-Aqsa and the Dome of the Rock, one of the holiest places in Islam. Jews refer to the area as Temple Mount, where an ancient Jewish temple once stood. It is the most sacred place in Judaism.

“The Israeli police have heightened security in and around Jerusalem and the Old City in order to prevent and respond to any incidents that could take place,” said spokesman Micky Rosenfeld, adding that undercover units had been deployed.

In an effort to limit the threat of violence, Israel also banned access to al-Aqsa for all men under 40 on Friday, the Muslim holy day. But rather than putting a cap on unrest, the restrictions risked further fuelling anger and frustration.

U.N. calls for calm at Jerusalem

The United Nations Security Council is expressing “grave concern” after violence this week at Jerusalem’s holiest site and is calling for restraint and calm.

The council statement was issued late Thursday after three days of clashes at the hilltop compound known to Muslims as the Noble Sanctuary and to Jews as the Temple Mount.

Rumors had spread among Palestinians that Jewish “settlers” were plotting to take over the site. Police entered the compound to disperse Muslim protesters who had holed up in the mosque and hurled rocks, concrete blocks and firebombs at security forces.

The council statement says Muslims at the site “must be allowed to worship in peace, free from violence, threats and provocations.”

It also says that “visitors should be without fear of violence or intimidation.”