UNITED NATIONS (Reuters) - United Nations Middle East envoy Nickolay Mladenov warned on Monday that a solution was needed by Friday to the Jerusalem mosque crisis, which he said threatens to have “potential catastrophic costs well beyond the walls of the Old City.”

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Israel installed metal detectors at entry points to Al-Aqsa mosque compound in Jerusalem after two police guards were shot dead on July 14, triggering the bloodiest clashes between Israelis and Palestinians in years.

Incensed at what they perceive as a violation of delicate decades-old access arrangements at Islam’s third-holiest site, many Palestinians have refused to go through the metal detectors, holding street prayers and often violent protests.

“It is extremely important that a solution to the current crisis be found by Friday,” Mladenov told reporters after briefing the U.N. Security Council behind closed doors. “The dangers on the ground will escalate if we go through another cycle of Friday prayer without a resolution.”

He also warned that the crisis was not a localized event.

“(It has) the potential to have catastrophic costs well beyond the walls of the Old City, well beyond Israel and Palestine, well beyond the Middle East itself,” Mladenov said.

The 15-member Security Council met on the crisis at the request of Sweden, France and Egypt.

Sweden’s Deputy U.N. Ambassador Carl Skau posted on Twitter after the meeting that Security Council members “agree on need for de-escalation, condemnation of violence and urgent dialogue to calm tensions in Jerusalem.”

The Security Council is due to hold its quarterly Middle East briefing on Tuesday. Mladenov appealed to member states to “avoid further inflaming the situation” when they address the public meeting.

The violence began on Friday, when Israeli security forces shot three demonstrators dead, Palestinian medics said. Israeli police said they were investigating the charge.

On the same day, a Palestinian stabbed three Israelis in the occupied West Bank after vowing on Facebook to take up his knife and heed “Al-Aqsa’s call.”

“We will enable everybody to come and pray on the Temple Mount, but at the same time we will do whatever is necessary to maintain security of this important site,” Israeli U.N. Ambassador Danny Danon said ahead of the meeting.

Palestinian U.N. envoy Riyad Mansour told reporters: “We are against violence ... and we want the Security Council to have the political will to protect the Palestinian people against such violence from the Israeli occupying authority.”