The U.S. military says Yemen’s Iran-backed Houthi rebels fired two missiles late Tuesday toward merchant ships traveling in the Red Sea near the strategic Bab el-Mandeb Strait. The U.S. Central Command said the missiles fell into the water, causing no injuries or damage. It was a rare direct statement on the attacks, and it came after reports from the British maritime security agency UKMTO. The UKMTO initially reported that a small boat with three armed persons on board had approached a container ship sailing between the coasts of Eritrea and Yemen to within 0.5 nautical miles. Still, it later said that after the ship fired warning shots, there was an exchange of fire, and the boat departed.

In recent weeks, the Houthis have targeted vessels they believe are linked to Israel in the Red Sea, firing drones and missiles at them and, in one case, boarding and seizing a Danish-flagged cargo ship. The attacks have upended shipping in the region, and significant global shipping companies like Denmark’s Maersk have told their ships to avoid the waters. The Houthis, who control much of Yemen, say they are striking the ships in solidarity with their Palestinian allies in Hamas.

On Sunday, a U.S. Navy destroyer and helicopters responded to a distress call from the Maersk Hangzhou after four small boats attacked it with small arms fire and attempted to board the ship, the U.S. Navy said. The USS Gravely and the MH-60R Seahawks opened fire on the boats, killing several of the armed attackers. The Maersk Hangzhou, a Singapore-flagged container ship, safely returned to port in the Yemeni city of Aden, and it did not suffer any damage.

This week, the United States announced that it was seeking to recruit partners for a new naval task force to help protect ships in the Red Sea. It will be a task force similar to the one currently in place in the Gulf of Aden, where 38 countries participate in combating piracy.

But despite the announcement, the U.S. hasn’t shown any indication that it intends to confront the Houthis directly in the region, and experts are doubtful whether a military response will be enough to make the Red Sea safe for shipping.

The rebels have seized territory in Yemen from the government for years, and they have been fighting a bloody war with the Saudi-led coalition supporting the government for more than three years. During that time, the United States has stepped up its support for the Saudi-led coalition in Yemen. It has armed the Saudi-led forces, and it is assisting them with logistics and intelligence.