TAL AFAR, Iraq (Reuters) -Iraq closed its border with Syria on Sunday to stop what it calls foreign fighters entering the country, as a U.S.-backed military operation to wipe out suspected terrorists in the city of Tal Afar continued.

Prime Minister Ibrahim Jaafari said on Sunday he was also imposing an overnight curfew in the north western region of Rabiah, on the main road from the Syrian border to the northern city of Mosul, near Tal Afar.

Thousands of Iraqi troops backed by U.S. forces launched an attack on rebels in Tal Afar starting at 2.00 a.m. on Saturday (2200 GMT on Friday). Defence Minister Saadoun Dulaimi said that after the assault, government forces were ready to strike insurgents in four other northwestern towns.

U.S. and Iraqi forces have long said Tal Afar was being used as a conduit for equipment and foreign Sunni Arab fighters smuggled in from Syria to fight the Shi”ite and Kurdish-led Iraqi government and occupying U.S. forces across the country.

Dulaimi said troops killed 141 insurgents and captured 197 on Friday and Saturday in Tal Afar, adding that all but three of 17 battalions — several thousand troops — involved were Iraqi.

The government has played up the lead role taken by Iraqi forces in the Tal Afar assault, keen to show that its fledgling U.S.-trained army is capable of carrying out such an operation. Previously such assaults have been led by U.S. troops.

U.S. officials say that 115 Iraqi battalions consisting of over 190,000 troops are now battle-ready after training by the U.S. military.

&#34Iraqi forces entered all sectors of the city in 11 operations, but they are still engaging in Hay al-Sarai district,&#34 an Iraqi defence ministry official said on Sunday, citing a military report covering the period 8.00 a.m. (0400 GMT) on Saturday to 8.00 a.m. on Sunday.

He added that Iraqi forces had killed three insurgents and arrested eight during that 24 hour period. He did not give their nationalities.

In its own statement, the U.S. military said Iraqi and Coalition Forces had captured 211 terror suspects, killed 141 terrorists and confiscated nine weapons caches, but made clear the figures dated back to Aug 26.

QUIET

Residents reported U.S. air strikes early on Saturday, gunfire and an encirclement of U.S. armour in parts of the town as Jaafari announced an offensive had begun.

But military operations were hampered later on Saturday by a sandstorm. Local residents said the vicinity of Tal Afar was quiet early on Sunday.

The Iraqi government is facing a Sunni Arab insurgency which it says is behind attacks on Iraqi police and soldiers and U.S. troops on a daily basis across the country.

The U.S. military statement said 41 &#34individuals suspected of terrorist activity&#34 had been detained on Saturday during a search in Tal Afar and had also seized a mortar system with multiple rounds of ammunition.

&#34Operation Restoring Rights is being conducted to remove terrorists and foreign fighters operating in Tal Afar,&#34 U.S. military spokesman Col. Billy J. Buckner said in the statement.

&#34This operation is in support of the Iraqi government”s efforts to bring safety and security to the citizens of the city.&#34

Dulaimi said that after the assault on Tal Afar, government forces were ready to strike insurgents in four other towns, Ramadi, Samarra, Rawa and Qaim, without saying when the attacks may start.

&#34This operation will take less time than you think … You will see in the next two days that our forces are capable and will flush the terrorists out and wipe them out.&#34