Israeli police forensic experts inspect the body of a Palestinian at the scene of an attack in the Al Aqsa Mosque compound in Jerusalem's Old City, Friday, July 14, 2017. Israeli police say three Palestinians have opened fire at Israelis near an important Jerusalem holy site, wounding two seriously before being killed in a gunfight. (AP Photo/Mahmoud Illean)

Jerusalem – Two Israeli policemen are in a serious condition and another is being treated for moderate injuries after three Palestinian gunmen opened fire on them at Al Aqsa Mosque in occupied East Jerusalem on Friday morning.

During an exchange of gunfire the three Palestinian gunmen were shot dead while the three injured Israeli policemen were evacuated to a Jerusalem hospital.

The Israeli police said the gunmen arrived at al Aqsa and noticed the policemen who carry out regular patrols around the mosque, the Israeli media reported.

The Palestinians then opened fire with improvised rifles and a pistol seriously wounding the two policemen and moderately wounding the third. They were subsequently shot dead after the police chased them and returned fire.

Two improvised rifles and a pistol were found on their bodies.

The mosque, Islam’s third-holiest site, was subsequently closed to Muslim worshippers on a day when hundreds of thousands of Palestinians come to pray. Friday prayers were also cancelled.

The last time Al Aqsa Mosque was closed to Muslims was in 2014 after the shooting and wounding of a right-wing Israeli, who is now a member of the Israeli parliament or Knesset.

Israeli security forces also closed off the Old City as investigations into the incident continued.

Israel’s Public Security Minister Gilad Erdan said that "the attack today is a difficult and severe event in which red lines were crossed. The attack is still under investigation and will require us to review all security arrangements at the Temple Mount (what Israelis call Al Aqsa) and its surroundings. I call on all public leaders to act to calm the situation and preserve the quiet in Jerusalem".

On Tuesday two Palestinians were shot dead during clashes with Israeli soldiers in the Jenin refugee camp in the northern Israeli-occupied West Bank.

On Monday, a Palestinian man was shot and killed after he attempted to run over and stab a group of soldiers near the West Bank settlement of Tekoa, near Bethlehem. A soldier was moderately wounded in the attack.

An Israeli paramilitary border policewoman was killed last month after three Palestinians armed with guns and knives carried out an attack on the border police just outside the Old City.