At least 450 Yemenis were killed in the first nine days of August, making it one of the bloodiest periods since the war broke out three and a half years ago between Houthi rebels and the Yemeni government. And it could get a lot worse.

An international coalition led by Saudi Arabia and the United Arab Emirates, and backed by the United States, is preparing to retake the strategic port city of Hodeidah. The operation could prove disastrous for Yemen’s most vulnerable: 70 percent of Yemen’s goods enter the country through Hodeidah, so a protracted battle could quickly turn into a humanitarian disaster where millions of people are prevented from receiving food and aid.

The U.N. is desperately trying to stop this attack and restart failed peace talks in the process. Its Special Envoy, Martin Griffiths, is hoping to bring all sides together in Geneva on Sept. 6.

Yet, government troops continue to advance toward the city.

“It’s going to be a fierce battle,” 23-year-old fighter Saeed told VICE News. “The Houthis have big military capabilities, but we are advancing toward Hodeidah.”

VICE News embedded with Yemeni troops as they prepared to retake a crucial Houthi supply route, just 90 minutes from the city. But even this seemingly straightforward operation descended into chaos. It wasn’t long into the advance that Saeed and several men found themselves cut off from their convoy, trapped by Houthi sniper fire. They were forced to run for cover before eventually making their escape.

“They must’ve known about our attack,” he said, as mortar fire raged around us.

A battle in Hodeidah city itself would be one of the deadliest in a war that has already claimed more than 10,000 lives and thrust 23 million more into the world’s worst humanitarian crisis. More than 120,000 civilians have fled the city in anticipation. It’s easy to see why. Not long after government forces started their push, ambulances began rolling up outside the one semi-functioning hospital in the area.

Ten-year-old Mohammed was the first civilian to be caught up in the crossfire. Ali Jalmoud says his son was playing in their house when a Houthi mortar hit. Dr. Mahdi Ba-Kather is the one remaining doctor in a local hospital, and he’s been struggling to cope with the influx of casualties. Mohammed had several shrapnel wounds — one hit an artery and staff trying desperately to control the bleeding.

“We’re tying it tight to stop it,” Dr. Ba-Kather explained to Mohammed as he used gauze as a makeshift tourniquet. Lacking basic supplies or a qualified surgeon, all he could do was triage Mohammed and send him to another hospital three hours away in the hopes he could survive the journey.

This segment originally aired August 15, 2018 on VICE News Tonight on HBO.