* Officials discuss plan for ousting al Qaeda in major cities
* Islamist militants took strategic positions last week
* Al Qaeda has been operating in border region for months (Adds Iran offer to help with army with equipment, if asked)
By Suadad al-Salhy
BAGHDAD, Jan 5 (Reuters) - Iraqi government forces battling an al Qaeda offensive near the Syrian border launched an air strike on Ramadi city on Sunday killing 25 Islamist militants, according to local officials.
Government officials in western Anbar province met tribal leaders to urge them to help repel al Qaeda-linked militants who have taken over parts of Ramadi and Falluja, strategic Iraqi cities on the Euphrates River.
Al Qaeda's Islamic State of Iraq and the Levant (ISIL) has been steadily tightening its grip in the vast Anbar province in recent months in a bid to create a Sunni Muslim state straddling the frontier with Syria.
But last week's capture of positions in Ramadi and large parts of Falluja was the first time in years that Sunni insurgents had taken ground in the province's major cities and held their positions for days.
Local officials and tribal leaders in Ramadi said that 25 suspected militants were killed in the air force strike, which targeted eastern areas of the city early on Sunday.
In Falluja, ISIL's task has been made easier by disgruntled tribesmen who have joined its fight against the government.
"As a local government we are doing our best to avoid sending the army to Falluja ... now we are negotiating outside the city with the tribes to decide how to enter the city without allowing the army to be involved," said Falih Eisa, a member of Anbar's provincial council.
One option being considered to oust al Qaeda from Falluja would be for army units and tribal fighters to form a "belt" around the city, isolating it and cutting supply routes for militants, military and local officials said.
They would also urge residents to leave the city.
"The siege could take days, we are betting on the time to give people a chance to leave the city, weaken the militants and exhaust them," a senior military officer who declined to be named said.
Tension has been running high across Anbar - which borders Syria and was the heart of Iraq's Sunni insurgency after the 2003 U.S.-led invasion - since Iraqi police broke up a Sunni protest last week, resulting in deadly clashes.
TRIBAL LEADERS HESITANT
In Tehran, the deputy chief of staff of Iran's armed forces for logistics and industrial research, Brigadier-General Mohammad Hejazi, was reported as saying on Sunday that Iran was ready to provide Iraq with "military equipment or consultation" to help the Iraqi army in Anbar if it were asked to do so.
The Tasnim news agency quoted him as adding however that he did not think the Iraqi army would need a deployment of Iranian troops, because they already had sufficient manpower.
Iran is an ally of Prime Minister Nuri al-Maliki's Shi'ite Muslim-led government.
Talks between Iraqi government officials and tribes made little headway on Sunday, with some tribal leaders hesitant to negotiate at all and others afraid of opposing al Qaeda, which has carried out numerous bombings and assassinations in Iraq.
"The militants told people in Falluja that they won't harm them and they are there in Falluja to exclusively fight the army, so this is the deal between the leaders in Falluja and the militants," a Sunni official involved in the negotiations in Anbar said.
Further west, across the porous border in Syria, al Qaeda fighters have captured swathes of land in the north and are battling with other Islamist brigades as well as the Syrian army.
The relationship between the fighters in Iraq and Syria is unclear, even though they refer to themselves as coming from the same group. Baghdad has said al Qaeda fighters from Syria are crossing into Iraq and have helped drive violence there to its worst levels in five years.
In Iraq, al Qaeda fighters had been controlling large parts of the desert in western Iraq along the Syrian border but have been driven back by a military campaign in recent days aimed at preventing them taking land.
In Ramadi, where tribesmen and the army have been working together to counter the al Qaeda insurgents, ISIL snipers positioned themselves on rooftops and fought small battles in the city.
ISIL fighters held on to their positions in the outskirts of Falluja and have used police and government vehicles inside the city for patrols, some flying a black flag associated with al Qaeda from the vehicles.
A tribal leader involved in negotiations in Falluja said the number of ISIL fighters in the outskirts of the city was insignificant and that fighting them might make matters worse.
"There is no reason to fight them and threaten the unity of the Sunni people. We believe that those who decide to fight alongside the government are wrong," he said. (Writing by Sylvia Westall; Editing by William Maclean, Ralph Boulton and Eric Walsh)