U.S.-led coalition warplanes launched their first airstrikes against Islamic State targets in Tikrit on Wednesday, March 25, officials said, coming off the sidelines to aid Iraqi forces fighting alongside Iran-backed Shi'ite militia on the ground, Reuters reported.

Iraqi Prime Minister Haider al-Abadi said Iraqi forces would prevail with the support of "friendly" countries and the international coalition, including arms, training and aerial support.

"We have opened the last page of the operations," Abadi said on state television.

A U.S. defense official, speaking on condition of anonymity, said American warplanes and aircraft from allied nations were striking up to a dozen targets in Tikrit, selected after coalition surveillance flights.

A second U.S. official, according to Reuters, stressed that Washington in no way would coordinate with the Iranian-backed militia or seek to empower them in Iraq, even if those fighters might share the same narrow tactical objective as Iraqi forces in Tikrit.

Lieutenant General James Terry, the senior U.S. commander of the U.S.-led coalition, said the strikes were aimed at enabling "Iraqi forces under Iraqi command."

"These strikes are intended to destroy ISIL strongholds with precision, thereby saving innocent Iraqi lives while minimizing collateral damage to infrastructure," Terry said, using an acronym for Islamic State.

As coalition aircraft entered the fray, Iraqi forces pounded Islamic State positions in Tikrit, resuming an offensive that had stalled for almost two weeks. Two military officers in the city confirmed Iraqi forces were shelling the militants.

"Military operations in Tikrit started at around 9 pm local time by pounding Islamic State positions with artillery, mortars and Katyusha rockets," said provincial council member Hadi al-Khazraji.

More than 20,000 troops and allied Shi'ite paramilitary groups have been taking part in the offensive and have suffered heavy casualties on the edge of the city, 100 miles (160 km) north of Baghdad.