The US will send about 3,000 more troops to the Middle East to support existing forces.

A Pentagon spokesman said troops would be sent to Kuwait as a preventative measure in response to an increased threat.

A total of 14,000 US troops have been deployed in the Middle East since May last year, AP reported.

Earlier, Pentagon said they killed the commander.

"At the direction of the President, the US military has taken decisive defensive action to protect US personnel abroad by killing Qasem Soleimani," a Pentagon statement said. "This strike was aimed at deterring future Iranian attack plans. The United States will continue to take all necessary action to protect our people and our interests wherever they are around the world."