United States Defence Secretary Robert Gates has said that a military buildup in the Gulf was a message to friends and 'potential adversaries' in the region and rejected the notion that the United States was on the verge of going to war with Iran.

"We are not planning for a war with Iran," he told media persons in Washington on Friday.

He said the decision announced in January to send a second US aircraft carrier to the Gulf region does not mean the US is planning for a war with Iran.

"The purpose of that (deployment) is simply to underscore to our friends, as well as to our potential adversaries in the region, that the United States has considered the Persian Gulf and that whole area and stability in that area to be a vital American national interest," he said.

"With respect to Iran, first of all, the President has made clear, the secretary of state has made clear, I've made clear -- nobody is planning -- we are not planning for a war with Iran. What we are trying to do is, in Iraq, counter what the Iranians are doing to our soldiers, their involvement in activities, particularly these explosively-formed projectiles that are killing our troops," Gates said.