Saudi Arabia is expected to announce a new multinational military coalition for the Red Sea in a bid to preempt Iranian-backed moves to restrict passage through the Bab el-Mandeb Strait. The Saudi-led initiative could be unveiled as early as Thursday, the deadline set for around 50 nations — including the United States, Pakistan, Egypt and Turkey — to confirm their participation, two senior diplomatic sources and a third senior US official speaking on background told Al-Monitor. Red Sea littoral states central to the effort, including Egypt and Sudan, have agreed to take part alongside Djibouti and Somalia, the sources said.

However, US support is seen as vital for the initiative to really take off. A well-placed source familiar with the discussions said there had been no decision from Washington as to whether to join the coalition, which will be headquartered in Riyadh and under Saudi command.

A Pentagon spokesperson did not return Al-Monitor's request for comment by publication time. US Central Command spokesperson Tim Hawkins declined to comment on Saudi Arabia's plans.

France, Germany and Italy are among a host of countries waiting for the United States to respond. "Everybody is waiting for the US to show its hand. Without real assets, this initiative won't take off," one of the officials said.