Tal Afar, Iraq ? More than 5,000 Iraqi army and paramilitary troops backed by U.S. soldiers swept into this insurgent stronghold near the Syrian border Saturday, conducting house-to-house searches and battering down stone walls in the narrow, winding streets of the old city.

Late Saturday, the prime minister ordered the Rabiyah border crossing closed in an attempt to stanch the flow of insurgents from Syria, which is about 60 miles from Tal Afar.

While several hundred insurgents using small arms initially put up stiff resistance in the city’s ancient Sarai district, Iraqi forces reported only two men wounded in the day’s fighting. The U.S. military issued no casualty report for the 3,500 Americans in the operation.

Interior Minister Bayan Jabr said 48 insurgents had been captured.

As the day wore on, fighting quickly died down, said Col. H.R. McMasters, commander of the 3rd Armored Cavalry Regiment. He said the joint force found the Sarai neighborhood nearly deserted once the shooting ended.

“The enemy decided to bail out,” he said, adding, however, that 150 insurgents had been killed the last two days. Jabr put the number at 141 and said five government soldiers died and three were wounded in the same period.

McMasters said the vast majority of insurgents captured in that period were “Iraqis and not foreigners.” Iraqi officials said Thursday that they had captured 150 foreign fighters.

U.S. Army soldiers walk over the demolished front gate of a house in order to search for weapons and insurgents Saturday in Tal Afar, Iraq.

South of Baghdad, police made the gruesome discovery of 18 men who had been handcuffed and shot to death after being abducted two days ago from their Shiite Muslim neighborhood in Iskandariyah, 30 miles south of the capital.

In recent weeks, dozens of bodies have been recovered, the apparent victims of tit-for-tat vengeance killings by Shiite and Sunni Arab death squads.

Baghdad International Airport reopened Saturday after a 24-hour closure, begun when a British security firm stopped working because it had not been paid for seven months. After overnight negotiations, the government agreed to pay half of what it owed, and employees of the London-based Global Strategies Group were ordered back to work.

With the Tal Afar offensive under way, the Iraqi defense minister signaled his U.S.-trained forces would not stop after this operation and vowed to move against insurgent bastions throughout the country.

“We say to our people … we are coming,” said Defense Minister Sadoun al-Dulaimi.

The offensive in Tal Afar, 260 miles northwest of Baghdad, is especially delicate because of the tangle of ethnic sensitivities.

About 90 percent of the city’s 200,000 people – most fled to the countryside before the fighting – are Sunni Turkmen who have complained about their treatment from the Shiite-dominated government and police force put in place after the U.S. invasion in 2003.

Addressing that complaint, Jabr announced Saturday that 1,000 additional police officers would be hired in Tal Afar after the offensive and that they would be chosen from the Turkmen population.

Twelve hours after the offensive began, Prime Minister Ibrahim al-Jaafari said insurgents had been trying to “to isolate Tal Afar from the political process as we are preparing for the referendum on the draft constitution.”