Kerry says US won't 'stand by' in Middle East as Iran steps up Yemen involvementSecretary of State John Kerry warned Iran over its increased involvement in Yemen’s civil war Wednesday, vowing that the U.S. would not “stand by” as the Middle East became destabilized. Meanwhile, Iran President Hassan Rouhani said Thursday that a Saudi-led campaign of airstrikes against Yemen’s Shiite rebels, known as Houthis, was a “mistake.” Rouhani did not single out any country in particular but said, “You learned that it was wrong. You will learn, not later but soon, that you are making mistake in Yemen, too.” Speaking on the “PBS Newshour” Wednesday, Kerry said that Tehran was “obviously” supplying the rebels, whose military advances forced Yemen’s U.S-and Saudi-backed president to flee last month. In response, Saudi Arabia and its Gulf allies have been carrying out airstrikes against Houthi targets since March 26. “Iran needs to recognize that the United States is not going to stand by while the region is destabilized or while people engage in overt warfare across lines — international boundaries — in other countries,” Kerry said. “We have an ability to understand that an Iran with a nuclear weapon is a greater threat than an Iran without one. And at the same time we have an ability to be able to stand up to interference that is inappropriate or against international law, or contrary to the region’s stability and interest and those of our friends.” Kerry’s interview was broadcast on the same day that Iran said it was sending a destroyer and another naval ship to the strategic Bab al-Mandab strait. Iranian Rear Adm. Habibollah Sayyari was quoted as saying that the ships were part of an anti-piracy campaign to “safeguard naval routes for vessels in the region” by the English-language state broadcaster Press TV. FULL REPORT