UNITED NATIONS (Reuters) - Several Gulf Arab states are unhappy about U.N. chief Ban Ki-moon’s call for an immediate ceasefire by all sides in Yemen and are expected to raise the issue in a meeting with him early next week, U.N. diplomatic sources said on Friday.

Ban on Thursday called for an immediate halt to the fighting, the first time he has made such an appeal since Saudi-led air strikes against Iranian-backed Houthi rebels began three weeks ago.

The main topic of the meeting will be the replacement for the outgoing U.N. envoy to Yemen Jamal Benomar, who announced his resignation on Wednesday. But, the sources said, they are also expected to raise their concerns about the appeal Ban made in a speech at the National Press Club.

The U.N. chief said the Saudis “have assured me that they understand that there must be a political process. I call on all Yemenis to participate in good faith.” He gave no indication that they supported his appeal to end military attacks.

“Gulf states are not happy about the speech and expect to make that point with the SG (Ban) in the meeting,” one of the diplomatic sources said on condition of anonymity.

Benomar, a veteran Moroccan diplomat, had irked Saudi Arabia and other Gulf nations with his handling of so-far unsuccessful peace talks between the Houthis and the Western- and Gulf Arab-backed Yemeni government, Western U.N. diplomats said on condition of anonymity.

Ban has chosen Mauritanian diplomat Ismail Ould Cheikh Ahmed, head of the U.N. mission combating the Ebola virus in West Africa, to replace Benomar, diplomatic sources said.

Saudi Arabia began air attacks in Yemen last month as Houthi rebels, who had taken control of the capital Sanaa in September, closed in on the port city of Aden and forced Yemeni President Abd-Rabbu Mansour Hadi to flee to Riyadh.

The Houthis and army units loyal to former president Ali Abdullah Saleh have been fighting alongside each other on several fronts against militia forces loyal to Hadi.

The United Nations said about 150,000 people had been driven from their homes by three weeks of air strikes and ground fighting and more than 750 people killed.

Iran’s foreign minister on Friday submitted a letter to Ban outlining a four-point peace plan for Yemen, but Western and Arab diplomats have shown little interest, saying they do not consider Tehran a neutral peace broker.