Updated

The U.N. humanitarian chief says it's critical to prevent a battle for the Yemeni port of Hodeida, which is a vital supply link to millions of Yemenis.

Mark Lowcock briefed the Security Council behind closed doors Monday and then told reporters that "90 percent of food, fuel and medicines in Yemen are imported" — and 70 percent come through Hodeida.

The aid group Oxfam said humanitarian organizations received warnings over the weekend for staff to evacuate Hodeida by Tuesday ahead of an offensive. Government forces, backed by a Saudi-led coalition, have been closing in on Hodeida.

Lowcock said: "It is our plan and intention to stay and deliver."

U.N. Secretary-General Antonio Guterres said that U.N. envoy Martin Griffiths is in "intense negotiations" with key parties to avoid a military confrontation.