Saudi Arabia proposed what it described as a new peace offering on Monday to end the kingdom’s nearly six-year-old war on the insurgency in neighboring Yemen, pledging to lift an air-and-sea blockade if the Houthi rebels agree to a cease-fire.

The offering, announced by Saudi Arabia’s foreign minister in Riyadh, the Saudi capital, came as pressure has escalated on the country to help break a stalemate in the Yemen conflict, which the United Nations has called the world’s worst man-made humanitarian disaster.

Millions of Yemenis, including children, are verging on famine partly because of the blockade, which has choked the delivery of food and fuel to the country, the Arab world’s poorest.

The Saudi foreign minister, Prince Faisal bin Farhan Al Saud, was quoted by Arab news media as saying that if the Houthis agreed to a cease-fire, the country would allow the reopening of the airport in Sana, the Yemeni capital, and would permit fuel and food imports through Hudaydah, a major Yemeni seaport. Both are controlled by the Houthis.

“The initiative will take effect as soon as the Houthis agree to it,” Prince Faisal was quoted as saying.

There was no immediate official response from the Houthis, but their leaders have said before that there would be no negotiations unless the blockades were lifted first. Many prior attempts aimed at halting the conflict have failed.

Saudi Arabia began an intense bombing campaign six years ago this week aimed at routing the Houthis, who had forced the Saudi-backed government to flee and still control a vast swath of Yemen. The Houthis are backed by Iran, which Saudi Arabia regards as its regional adversary.

Saudi-led bombings and Houthi attacks have devastated Yemen’s fragile economy and led to widespread civilian casualties, and 80 percent of the country’s roughly 30 million people require humanitarian help. By some estimates nearly a quarter million Yemenis have been killed in the conflict, and millions face acute hunger or starvation.

The Saudi announcement came just a few weeks after President Biden, breaking with the previous administration of Donald J. Trump, announced an end to American logistical and intelligence support for the Saudi war effort in Yemen.

United Nations humanitarian officials have been pleading for eased access to vulnerable Yemenis isolated by the war, warning that famine already is beginning to take hold. After a visit to Yemen in early March, David Beasley, executive director of the World Food Program, the U.N.’s anti-hunger agency, said “the famine is on a worsening trajectory.”

Six years of war, Mr. Beasley said, had “completely devastated the people, in every respect.”