Fighters of the Islamic State in Iraq and the Levant (ISIL) have captured the western Iraqi town of al-Baghdadi, putting them within striking distance of an airbase where US troops are training Iraqi forces, the US military said.

The fall of the town, which the Pentagon played down as a minor setback, came as ISIL launched an unsuccessful assault involving suicide bombers on the nearby al-Asad airbase.

"We do assess that right now they have control of Al-Baghdadi," Pentagon spokesman Rear Admiral John Kirby told a news conference, adding ISIL took hold of the town "in the past several days".

The town is located in Anbar province, about 8km from the al-Asad air base, where about 320 US Marines are stationed to assist Iraqi government troops.

The chairman of Anbar's provincial council, Sabah Karhout, said "more than 1,000 ISIL fighters" had overrun the town of al-Baghdadi".

Karhout said that "there is a regional plot that wants the base to fall under ISIL because of its strategic significance", adding that the US-led coalition air strikes that targeted the vicinity of the base did not hit their targets.

Iraqi Defence Minister Khaled al-Obeidi described what happened in the city of al-Baghdadi as "a failure".

The minister made the comments after a meeting with the parliamentary security committee.

He said his ministry was planning to deploy more forces to address the situation.

Kirby said that "at no time were US troops anywhere near the fighting," which was about two miles away from where the Americans were working at the sprawling complex.

'Defensive posture'

"This is arguably the first in at least a couple of months, if not more, where they (ISIL) have had any success at all at taking any new ground," Kirby said.

"So this is an enemy that we still assess to be in a defensive posture," he said, adding: "It's one town. It's not all of Anbar. It's not all of Iraq. We need to keep it in perspective."

Al-Baghdadi had been under growing pressure for months and was one of the few towns that had remained under the Iraqi government's control in the predominantly Sunni province.

Meanwhile, 12 people - including a Sunni tribal leader and two sons of an Iraqi MP -were killed in Baghdad on Friday hours after they were kidnapped by a Shia armed group.

Parliamentary sources told Al Jazeera the tribal leader, Qassim Sueidan Al-Janabai, belonged to the al-Janabat clan.

The victims were seized when a convoy of Zaid Swidan al-Janabi, a Sunni MP, was stopped by militiamen in al-Dorah, a neighbourhood in al-Rashid administrative district in southern Baghdad.

The MP was later released in the neighbourhood of Talbiya, east Baghdad but after he was badly beaten up.

Interior Ministry spokesman Saad Maan, who addressed reporters, described the incident as "tragic," adding that the ministry had launched an investigation.

Source: Al Jazeera and agencies