Police and masked rioters clashed on Jerusalem’s Temple Mount Wednesday morning, as tensions ramped up ahead of the Jewish holiday of Sukkot.

Rioters were chased by police into the al-Aqsa Mosque, located on the Mount’s esplanade, after fighting broke out following the opening of a gate for non-Muslim visitors.

Protesters inside the mosque tried to spray flammable liquid out of windows toward officers.

They also threw Molotov cocktails from within the mosque for the first time, according to Israel Radio.

Four policemen were wounded in the clashes, and 15 arrests were made, according to police.

The Palestinian Ma’an news agency reported dozens of Palestinians were injured in the clashes.

The agency reported a fire broke out in the mosque after a stun grenade was thrown by police officers.

There was no immediate comment from police.

The fighting began when masked youths threw stones, iron bars, cinder blocks and Molotov cocktails at police officers as the Mughrabi Gate opened to non-Muslim visitors earlier in the day.

Police chased the demonstrators toward the Al-Aqsa mosque, where they barricaded themselves inside and continued hurling objects in the direction of the police, said police spokeswoman Luba Samri.

Samri said the Palestinians had prepared for the confrontation ahead of time, and had set up obstacles at the holy site to slow down police. She said the Palestinians threw firebombs and rocks at police from within the mosque.

Police responded with “nonlethal riot control means,” Samri said.

A radical Islamic cleric in Israel, Raed Salah, had called on Muslims to be present at the mosque Wednesday morning. About 30 young Palestinians slept the night before at the mosque in preparation for the confrontation, according to Palestinian eyewitnesses.

The skirmish came as Israeli Jews prepared for the holiday of Sukkot, which begins Wednesday night. Many Jews have the custom of visiting the Temple Mount on holiday eves, ramping up tensions on the contested site.

The Mughrabi Gate has been the site of frequent clashes between Israeli security forces and Muslim worshipers, due to a commonly perceived belief among the local Islamic community of Jewish encroachment onto the Temple Mount.

Last month saw violent clashes in and around the Temple Mount compound ahead of the Rosh Hashanah holiday.

The clashes came amid an uptick in inter-ethnic violence in Jerusalem over the past several months, with incidents of East Jerusalem rioters hurling stones and Molotov cocktails and using fireworks as a weapon.

Police have cracked down on the protests, arresting suspected rioters in overnight sweeps and bolstering their presence in flashpoint areas.

Police said Wednesday they had arrested two men in their 20s for throwing stones at passing cars and the Jerusalem light rail.

Prime Minister Benjamin Netanyahu ordered police to up patrols in East Jerusalem Tuesday, saying he would not allow riots to become the norm, Israel Radio reported.

The Temple Mount, which holds the Dome of the Rock and al-Aqsa Mosque, is considered the third-holiest site in Islam and the holiest site for Jews as it was the location of the two ancient Jewish temples.

In September, an addition to the Mughrabi Bridge meant to boost the flow of non-Muslim visitors to the Temple Mount was dismantled after it was deemed “illegal” by Netanyahu. The move, which was praised by Jordan and the Islamic authorities of the site, was seen by some as an attempt to decrease tensions.

AP, Justin Jalil and Spencer Ho contributed to this report.