ADEN (Reuters) - The Saudi-led military coalition fighting against the Houthi movement in Yemen has reopened a land border crossing, easing a blockade imposed on the country earlier this week, a Yemeni official and witnesses said on Friday.

The coalition said on Monday it would close all air, land and sea ports in Yemen to stem the flow of arms to the Houthis from Iran, after Saudi Arabia intercepted a missile fired toward its capital Riyadh.

The al Wadea border crossing, linking Saudi Arabia with territory in eastern Yemen controlled by the Saudi-backed government, was reopened on Thursday, the official and witnesses said, letting food and other supplies enter Yemen.

The United Nations has said that a total blockade could cause a famine that could kill millions. The southern port of Aden was reopened on Wednesday.

The Houthis, drawn mainly from Yemen’s Zaidi Shi’ite minority and allied to long-serving former president Ali Abdullah Saleh, control much of the country including the capital San’aa. Saudi Arabia and its Arab allies have been waging war against them on behalf of the government of President Abd-Rabbu Mansour Hadi, based in Aden.

United Nations aid chief Mark Lowcock said on Wednesday that if the coalition did not allow humanitarian aid access to Yemen, it would cause “the largest famine the world has seen for many decades, with millions of victims.”

The Saudis and their allies say the Houthis get weapons from their arch-foe, Iran. Iran denies arming the Houthis and blames the conflict in Yemen on Riyadh.