DAMASCUS, Syria — Tens of thousands of Syrians turned out today for a massive government-orchestrated protest against a deadly U.S. raid near the Iraqi border.

A mile away, hundreds of Syrian riot police formed a protective ring around the closed U.S. Embassy, but the flag-waving crowds dispersed peacefully after a couple of hours later, with students heading to schools and employees to work.

The troops, wearing helmets and armed with batons and shields, took up positions around the embassy and the adjacent U.S. residence building. The embassy was closed because of security concerns related to the protest, and the American school in Damascus was also shut for the day.

The protest came as Syria demanded a formal apology from the U.S. for Sunday’s attack in the eastern border community of Abu Kamal that Damascus says killed eight civilians. It threatened to cut off cooperation on Iraqi border security if there are more American raids on Syria territory.

There has been no formal acknowledgment of the raid from Washington. But U.S. officials, speaking on condition of anonymity, have said the target of the raid was Badran Turki al-Mazidih, a top al-Qaida in Iraq figure who operated a network of smuggling fighters into the war-torn country. The Iraqi national also goes by the name Abu Ghadiyah.

Syria insists the dead were civilians and has challenged Americans to provide evidence to the contrary.

“This aggression did not succeed,” said Information Minister Mohsen Bilal. “It was supposed to yield a catch so that they could show it to the world ... But the catch turned out to be an innocent family.”

No violence was reported at today’s rally on the Youssef al-Azmi square and surrounding streets in the upscale al-Maliki neighborhood. Some young Syrians formed circles and danced traditional dances while women and students joined the peaceful crowds.

Protesters waved national flags, carried pictures of President Bashar Assad and held banners, one of which called America “the sponsor of destruction and wars.”

Hussam Baayoun, a 20-year-old university student at the rally, said the U.S. raid was a “criminal act” and added: “We want the Americans to stop their acts of terrorism in Syria, in Iraq and the rest of the world.”

In Washington, State Department deputy spokesman Robert Wood said Wednesday that Syria had formally notified the U.S. of the closure order for the cultural center, effective immediately, and the school by Nov. 6.

Wood said Washington was considering how to respond and that the U.S. expects the Syrian government to “provide adequate security for the buildings.”

Though Syria has long been viewed by the U.S. as a destabilizing country in the Middle East, in recent months, Damascus has been trying to change its image and end years of global seclusion.

But American accusations that Syria wasn’t doing enough to prevent foreign fighters from crossing its borders into Iraq remains a sore point in relations. Syria says it is doing all it can to safeguard its long, porous border.