Fighter aircraft struck an SA-13 surface-to-air missile launcher and a vehicle for a surface-to-surface missile system in the south near Basra, and three Russian-made multiple rocket launchers near Mosul in the north, officials said.

They were the latest in an almost daily series of airstrikes that have helped clear the way for a threatened US-led invasion by stripping away Iraqi air defenses and offensive ground-to-ground missile systems.

Meanwhile, the Iraqi military appeared to be repositioning armor and other heavy forces around Baghdad.

US intelligence has detected movements of large flatbed trucks capable of carrying tanks and other heavy armor in the direction of the Iraqi capital, a US official said, speaking on condition of anonymity.

Iraq may also be moving more surface-to-surface and surface-to-air systems into no-fly zones patrolled by US and British aircraft in response to the US buildup, a US defense official said.

"They move them around, and when we see them -- and they pose a threat -- we plink them," said the official, who asked not to be identified.

The strike in the north -- the first in more than three weeks by US and British aircraft operating from Turkey -- came after Washington and Ankara reached a tentative agreement that would allow US ground forces to stage an offensive into northern Iraq from Turkey.

The three Iraqi multiple launch rocket systems detected near Mosul were attacked by US Air Force F-16 fighters operating from Incirlik Air Base in Turkey, a second US defense official said.

"Coalition aircraft engaged the mobile missile launchers approximately six miles (10 kilometers) south of Mosul and then continued to enforce the no-fly zone in northern Iraq," the US European Command said.

There was no word if the launchers had been destroyed, because damage assessment was still underway.

Two US Navy F/A-18 fighters went into action hours later in the south, dropping two precision guided bombs on an SA-13 surface-to-air missile launcher 50 kilometers (30 miles) from Basra , the official.

Three hours after that strike, a pair of F-16 fighters bombed a vehicle used to carry missiles for a surface-to-surface missile system, the official said.

"The coalition executed today's strike after Iraqi forces moved the mobile missile system into range of coalition forces in Kuwait," the US Central Command said.

Most US and British airstrikes have targeted elements of Iraq's air defense systems -- radars, fiber-optic links, mobile radars, surface-to-air missiles, anti-aircraft artillery and the command centers that coordinate them.

Attacks on surface-to-surface systems have been rare, however.

On February 11 and 12, coalition warplanes struck an Iraqi short-range missile system near Basra that was in striking range of US troops massing in nearby Kuwait.

Iraqi anti-ship missile systems on the Al Faw peninsula that juts into the Gulf also have been targeted on occasion in the past because they posed a threat to US warships.

But Tuesday's airstrikes were the first to target surface-to-surface missiles in the north, where US and British aircraft have been enforcing a no-fly zone since 1991.

They came as thousands of US troops were readying for deployment into Turkey pending a green light from Turkish parliament.

If President George W. Bush gives the signal for war, plans call for US forces to open a second front in northern Iraq, pouring across the Turkish border to secure oilfields near Mosul and Kirkuk, and to drive on to Tikrit, Iraqi President Saddam Hussein's hometown and power base.

US and British aircraft flying from Incirlik Air Base in Turkey have been enforcing a no-fly zone over northern Iraq as part of Operation Northern Watch since 1991. A similar no-fly zone also was imposed in the south after the Gulf War.

The last time they struck Iraqi forces in the north was on January 31, when coalition jets bombed Iraqi anti-aircraft artillery based about 10 mileskilometers) east of Mosul.

In the south, US strategic B-52 bombers began practice runs over an unspecified northern part of the Gulf region Sunday "to maintain aircrew proficiency and familiarization," according to the US Central Command.