DUBAI: Yemeni government forces and their Arab allies are massing north and south of the Houthi-held Red Sea port of Hudaida despite U.N. and aid groups’ warnings that a military operation there would put millions of civilians at risk.

Hudaida port and province is controlled by the Iran-aligned Houthis and has been the entry point for 70 percent of Yemen’s food supplies as well as humanitarian aid.

The country has been torn by more than two years of civil war that pits the armed Houthi group against the government of President Abed Rabbou Mansour Hadi, which is backed by an Arab alliance. More than 10,000 people have been killed in the conflict and hunger is widespread.

Local officials said that Hadi’s government, building on recent gains that included capturing the coffee export hub of Mokha in February, has amassed two recently trained brigades – one in Midi about 230 kilometers north of Hudaida near the border with Saudi Arabia, and another outside the Khoukha region, some 130 kilometers south of the city.

Government forces will have to cross large areas of Houthi-held territory from both sides as the movement still controls the most populated areas in Western Yemen, including the capital Sanaa, and the regions surrounding the port city.

Mohsen Khasrof, a senior military official in Hadi’s Aden-based government, said it was only a matter of time for an attack on Hudaida to start after the United Nations rejected coalition demands that it take steps to ensure no weapons reach the Houthis through it. “The political decision of liberating Hudaida has been taken and military preparations have been completed, only the timing remains to be decided,” he told Reuters by telephone.

The Houthis have also been preparing their defenses. “Tens of thousands of our fighters from the tribes have answered the call of [the Houthi leader] Abdel-Malek al-Houthi,” deputy spokesman of forces fighting alongside the Houthis, Aziz Rached, told Yemeni news agency Khabar Tuesday.

Food deliveries have been cut by more than half with nearly 3.3 million people – including 2.1 million children – acutely malnourished, the United Nations says.

The coalition of Arab countries might still be waiting for a go-ahead from its Western allies before the launch the Hudaida offensive, Yemeni government sources said.

It was unclear whether U.S. President Donald Trump’s administration would approve such a move.

His predecessor, Barack Obama had been wary of any operations involving the port and last year rejected a proposal to assist its Gulf allies in a push to take control of it. The Arab coalition has accused the Houthis of using the port to smuggle weapons and ammunition, and has been calling on the U.N. to post monitors at the port, which had been damaged by coalition airstrikes. The Houthi movement denied the claims.The United Nations checks ships heading to Hudaida in Djibouti while passing through the Bab al-Mandab Strait, but Hadi’s government says the system was flawed.