WASHINGTON (AP) — The U.S. will send hundreds of additional troops and a dozen fighter jets to the Middle East in the coming weeks to counter what the Pentagon said is an escalating campaign by Iran to plan attacks against the U.S. and its interests in the region. And for the first time, Pentagon officials on Friday publicly blamed Iran and its proxies for recent tanker bombings near United Arab Emirates and a rocket attack in Iraq.

President Donald Trump told reporters Friday that the 1,500 troops would have a “mostly protective” role as part of a build-up that began this month in response to what the U.S said was a threat from Iran, without providing details or evidence.

Vice Admiral Michael Gilday told Pentagon reporters that the U.S. has “very high confidence” that Iran’s Revolutionary Guard was responsible for the explosions on four tankers, and that Iranian proxies in Iraq fired rockets into Baghdad. He said Iran also tried to deploy modified small boats that were capable of launching cruise missiles.

The deployments announced Friday include a squadron of 12 fighter jets, manned and unmanned surveillance aircraft, and a number of military engineers to beef up protection for forces. In addition a battalion of four Patriot missile batteries that were scheduled to leave the Middle East has been ordered to stay. The total number of troops involved is about 1,500, with roughly 600 included in the Patriot battalion.