TEHRAN (Reuters) -Iran dismissed on Sunday U.S. naval war games on its doorstep as a morale-boosting exercise for American soldiers, days after a large flotilla of U.S. ships entered the Gulf in a show of military muscle.

“This coming and going (of U.S. military ships in the Gulf) is nothing new,” Foreign Ministry spokesman Mohammad Ali Hosseini told reporters at a weekly briefing. “It seems these movements are for lifting the spirits of the American soldiers.”

Tension between Tehran and Washington has been mounting in recent months over Iran’s disputed nuclear plans and the conflict in Iraq, helping to send world crude prices higher over fears of possible supply disruption from the oil-rich region.

Two nuclear-powered aircraft carriers were among the group of U.S. ships which began war games in the Gulf last Thursday.

The ships, carrying about 17,000 personnel and 140 aircraft, will take part in war drills over the next two weeks, the U.S military says.

Iran frequently holds its own war games in the Gulf, earlier this year test-firing missiles which a commander said could sink big warships.

U.S. and Iranian ambassadors are due to meet on Monday in Baghdad to discuss security in Iraq, a rare encounter for the two foes which have not had diplomatic ties since after Iran’s 1979 Islamic revolution that overthrew the U.S.-backed Shah.

The United States accuses Iran of fomenting instability in Iraq by supporting Shi’ite militia there. Tehran denies the charge and blames the presence of U.S. troops for the bloodshed across the border.

Iran also denies western accusations that it is seeking nuclear bombs, saying its nuclear programe is designed purely to generate electricity.