US vice president, Iraqi PM discuss military operations

US Vice President Joe Biden on Wednesday called Iraqi Prime Minister Haider al-Abadi to talk about ongoing military operations in Iraq.

"The vice president specifically welcomed the prime minister’s call from the frontlines for the protection of civilians and the importance of ensuring all armed groups act under control of the state," Biden’s office said in a statement.

Iraqi security forces, backed by the US-led international coalition and tribal fighters, have launched an operation against Islamic State (IS) group targets in the Anbar province in western Iraq where 38 IS militants were killed on Wednesday.

An offensive on Tuesday in the northern province of Saladin killed 25 militants, according to the Iraqi military. Iraqi troops were supported by al-Jabbour tribal fighters and the al-Hashid al-Shabi Shiite militia in the clashes that took place near the city of Tikrit, the hometown of former president Saddam Hussein.

Biden’s office said the vice president “commended Prime Minister Abadi and other Iraqi leaders for building a national front before launching the ongoing operation near Tikrit".

Biden also acknowledged the Iraqi government’s efforts to enable fighters from Saladin to participate in reclaiming their own territory from IS and to ensure displaced populations can return to their homes after the group is defeated and local areas are stabilised.

Meanwhile, the US warned that an offensive to retake control of Tikrit from IS must not fuel sectarian tensions.

"It is important - and Prime Minister Abadi himself has indicated ... that this operation should not be used as an excuse or as cover for individuals taking sectarian-motivated retribution," said White House spokesman Josh Earnest.

"That would tear at the fabric of the country, and weaken the ability of the Iraqis to confront this threat to their country."

"Iranian forces are also involved," Earnest acknowledged. "We have said from the beginning that the United States will not coordinate militarily with the Iranians."

The presence of Shiite militia and Iranian forces has prompted fears that the majority-Sunni city could be the scene of revenge attacks that have been a feature of previous assaults.

"The fact that some Iranian military personnel are involved doesn't change the priority that the Iraqis can and should place on this operation to ensure that it's inclusive and multisectarian," said Earnest.

Also on Wednesday, US prosecutors announced that a Californian man who tried to travel to Syria last year was charged with attempting to join IS.

Adam Dandach, 21 - also known as Fadi Fadi Dandach - was charged with trying to provide support to a foreign terrorist group and making a false passport application statement to facilitate terrorism, they said.

He was also indicted on one count of obstruction of justice for attempting to destroy records after his arrest last July. If convicted of all the charges, Dandach could face up to 25 years in prison.

When arrested Dandach told FBI agents that he was traveling to Syria "for the purpose of pledging his alliance and assistance to the Islamic State of Iraq and Syria, or ISIS," according to court documents.

He added that "he believed the killings of American soldiers are justified", they said.