Saudi Arabia's foreign minister on Thursday urged the US-led coalition conducting air strikes against the Islamic State group in Syria and Iraq to wage a ground war against the jihadists.

The kingdom, part of that coalition, "stresses the need to provide the military means needed to face this challenge on the ground," Prince Saud al-Faisal said at a news conference with US Secretary of State John Kerry.

Several Arab countries have joined the air campaign against IS.

President Barack Obama, anxious to avoid a drawn-out ground war, has backed an air campaign, but ruled out deploying infantry.

The Saudi minister also warned of Iran's growing role in Iraq, accusing the Shiite-dominated Islamic republic of "taking over" the kingdom's Arab neighbour through its aid in the fight against IS.

"Tikrit is a prime example of what we are worried about. Iran is taking over the country," Faisal said of the late Iraqi dictator Saddam Hussein's hometown.

The US military's top officer, General Martin Dempsey, said Tuesday that Iran's help in an Iraqi offensive to recapture Tikrit could be "a positive thing" providing it did not fuel added sectarianism.

On Thursday the United Nations said military operations aimed at retaking Tikrit from IS have caused about 28,000 people to flee their homes.

"We have urged all Iraqi forces to avoid and prevent the abuse to civilians of any kind of activity that violates international norms, fuels sectarian fears, and promotes sectarian divides, and that includes Iran in terms of their activities," Kerry said.

About 30,000 Iraqi security force members and allied fighters launched an operation to retake Tikrit on Monday.

Sunni-dominated Saudi Arabia is wary of the ambitions of its arch rival Iran across the Gulf.

British teacher jailed for trying to join IS
London (AFP) March 5, 2015 - A chemistry teacher was jailed for six years in Britain on Thursday for trying to join Islamic State jihadists fighting in Syria, against the wishes of his family who desperately tried to stop him.

Jamshed Javeed, 30, one of a group of radicalised Muslims from Manchester in northwest England, was arrested in December 2013 as he was about to travel to the Middle East -- after helping his younger brother and three others make the same trip.

At the high-security Woolwich Crown Court in southeast London, judge Michael Topolski said Javeed was "adherent to a violent jihadist mindset" and should be considered "dangerous".

The teacher pleaded guilty in October to two counts of engaging in conduct in preparation of terrorist acts, but insisted he was not an extremist and had never supported the aims of IS "as now revealed and understood", the court heard.

But Topolski told Javeed he was "not satisfied that you reject its ultimate aims".

The judge said: "You had become sufficiently radicalised and committed to a violent jihadist ideology that you were part of a group of young men determined to travel to Syria to join ISIS (Islamic State) and to fight and die for them."

He said Javeed ignored the pleas of his wife and family and persisted even after they had hidden his passport and his equipment such as solar chargers.

"Even the prospect of becoming a father did not deter you," said the judge.

"You were not planning to return to this country... but rather to die, if you could, as a martyr.

"Whether you believed you were fighting in a just cause is irrelevant. The law is clear: this was terrorism."

The court heard how his wife's revelation that she was pregnant with their daughter did not deter Javeed.

In a text message, she had said: "Jamshed, you refuse to take on board anyone's opinion unless I've got a gun and I'm in Syria."

Police praised his family's "brave steps" in trying to thwart his plans.

Javeed was among a group of young Muslim men from Manchester who became radicalised in 2013.

His brother and two of the three other men he helped go to the Middle East have not been heard of since. The other one is confirmed dead.