By Nayera Abdallah, Eman Abouhassira and Enas Alashray DUBAI/CAIRO, July 20 (Reuters) - Yemen's Iran-aligned Houthis said on Monday they were imposing a naval blockade on Saudi Arabia, a move that opens a new front against the United States in its war on Iran and widens the threat to global energy supplies and trade beyond the Gulf. Iran had pressed the Houthis to close the Bab el-Mandeb gateway to the Red Sea if the U.S. continued to attack Iranian power infrastructure.
