A top US envoy said Iraqi troops would launch a major ground offensive against the Islamic State group in the coming weeks, as a suicide bomber killed 14 people in Baghdad Monday.

IS spearheaded an offensive that swept through large areas north and west of Baghdad last June, and Iraqi forces are battling to regain ground with support from US-led air strikes.

Jordan announced it has carried out dozens of strikes against the jihadists since Thursday, as it seeks to avenge an airman burned alive by the group.

John Allen, the US coordinator for the anti-IS coalition of Western and Arab countries, said Sunday Iraqi troops would begin a major offensive "in the weeks ahead".

"When the Iraqi forces begin the ground campaign to take back Iraq, the coalition will provide major firepower associated with that," he told Jordan's official Petra news agency.

Iraqi forces have already carried out operations near Baghdad and in Diyala and Salaheddin provinces north of the capital.

IS-led militants were stopped short of Baghdad in June and have since been pushed back, but can still carry out deadly attacks.

On Monday, a suicide bomber attacked Baghdad's Shiite-majority Kadhimiyah district, killing at least 14 people and wounding at least 43, officials said.

The bomber struck near pavement vendors in crowded Aden Square in the second suicide bombing to hit the city in three days.

On Saturday, an attack inside a restaurant in the Baghdad Jadida area killed at least 23 people.

- Gruesome video -

There was no immediate claim of responsibility for Monday's attack, but suicide bombings are almost exclusively carried out by Sunni extremists in Iraq, including IS.

Jordanian air force chief Major General Mansour al-Jobour said Sunday the kingdom had launched 56 strikes against the jihadists since Thursday as part of the US-led air campaign.

Jordan had vowed an "earth-shattering" response after IS captured one of its pilots and released gruesome video of him apparently being burned alive.

"On the first day of the campaign to avenge our airman Maaz al-Kassasbeh, 19 targets were destroyed, including training camps and equipment," Jobour told reporters.

Strikes since Thursday had destroyed dozens of targets.

US Secretary of State John Kerry said the air campaign, launched in Iraq in August and expanded to Syria the following month, was helping ground forces win back territory and depriving the jihadists of key funds.

There have been 2,000 air strikes on IS so far, Kerry told a security conference in Munich.

These had helped ground forces retake some 700 square kilometres (270 square miles) of territory from the jihadists, or "one-fifth of the area they had in their control", he said.

Kerry did not specify whether the recaptured territory was in Iraq or Syria.

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But he added the coalition had "deprived the militants of the use of 200 oil and gas facilities... disrupted their command structure... squeezed its finance and dispersed its personnel".

Syrian Foreign Minister Walid Muallem said on Monday foreign troops would not be allowed on the ground in Syria to battle IS, also telling journalists Amman had not responded to a Damascus request to coordinate efforts against the jihadists.

Britain-based monitor the Syrian Observatory for Human Rights said Sunday Kurdish forces had retaken more than a third of the villages around Kobane, a strategic town on the Syrian-Turkish border.

The Kurds recaptured Kobane on January 26 after four months of fierce fighting backed by Syrian rebels and coalition air strikes.

Coalition warplanes launched three air strikes against IS in Syria in the 24 hours to 0600 GMT on Monday, the Pentagon said, and another six in Iraq.

The Observatory also reported at least 15 people killed and dozens wounded on Monday in Syrian regime air strikes on the rebel-held Douma area east of Damascus.

As Jordan stepped up its air war, IS claimed on Friday that American aid worker hostage Kayla Jean Mueller, 26, had been buried alive under rubble by a coalition strike on its self-proclaimed capital of Raqa in Syria.

Mueller's parents said they were hopeful she was still alive, while US Secretary of Homeland Security Jeh Johnson said Washington was seeking clarification on her fate.