U.S. diplomatic chief Marco Rubio yesterday Friday, appealed for restraint to the warring sides in Yemen, avoiding taking sides between Saudi Arabia and the United Arab Emirates, strategic partners of the United States involved in the escalating hostilities.

“We call for restraint and the continuation of diplomatic efforts to reach a viable solution,” Marco Rubio said. “We are grateful to our partners, the Kingdom of Saudi Arabia and the United Arab Emirates, for their leading diplomatic role,” he added.

Yemen’s internationally recognised government today called on the Saudi-led coalition to take “military action” to support its forces in territory recently seized by separatists. For their part, the separatists of the Southern Transitional Council (STC) – which is backed by the United Arab Emirates – accused Saudi Arabia of hitting their positions and reiterated that they are determined to continue until they achieve their objectives. This separatist movement has recently seized large swathes of territory and says it wants to reestablish the state of South Yemen, which was independent from 1967 to 1990.

More than 15,000 Saudi-backed Yemeni fighters have gathered in strategic zones on the border between the two countries, according to a military official. Riyadh may consider taking military action against the separatists if negotiations fail, the same source said.

Since 2014, Yemen has been mired in a devastating war between Iranian-backed Houthi rebels and the internationally recognised government backed by disparate forces. The intervention of the Saudi-led military coalition in 2015 exacerbated the conflict, leaving behind a country divided, hundreds of thousands dead, and one of the world’s worst humanitarian crises.