After months of criticism, Secretary-General Kofi Annan decided that UN refugee chief Ruud Lubbers had to go because of the growing controversy over allegations that the former Dutch prime minister had sexually harassed female staffers.

Lubbers didn't go easily. He resigned on Sunday but proclaimed his innocence, saying he felt insulted and accusing Annan of giving in to "media pressure".

At a meeting with Annan on Friday, UN diplomats said the secretary-general offered the UN High Commissioner for Refugees two choices resign or face suspension and charges of breaking UN rules.

Allegations first surfaced last year that he had made unwanted sexual advances to a female employee. But it was only on Friday that the British newspaper The Independent published the first detailed description of her allegations and statements from four other women who didn't file official complaints but claimed Lubbers sexually harassed them.

As the United Nations struggles to improve its image in the face of scandals over the UN oil-for-food programme and sexual abuse by UN peacekeepers in Congo, diplomats said Annan decided that Lubbers had become a liability but he was also a fighter.

After defiantly telling reporters that Annan had not asked for his resignation and he intended to complete his five-year term, Lubbers flew home to Geneva on Friday. But after he left UN headquarters, Annan's office contradicted the refugee chief, saying the prime topic of the meeting was his future.

Ahead of the axe

UN lawyers then started preparing charges against him, UN diplomats said on condition of anonymity.

Apparently knowing what was coming, Lubbers, 65, decided to resign on Sunday before being suspended.

In his letter of resignation, Lubbers maintained his innocence, indicating that Annan wanted him to step down.

"For more than four years I gave all my energy to UNHCR," he said. "Now in the middle of a series of problems and with ongoing media pressure you apparently view this differently."

"To be frank, and despite all my loyalty, insult has now been added to injury and therefore I resign as high commissioner," Lubbers said.

On Friday, he insisted the allegations of sexual harassment were "made up" and "slander".

He vehemently denied the female employee's allegation that he put his arms around her waist, pulled her back toward him and pressed his groin into her at the end of a meeting in December 2003.

"There were two witnesses in the room who very clearly saw that I ushered the lady out of the room with my hand on her back, and that was all," he said. "I call it familiar but certainly not sexual harassment."

Annan had been criticised for months for rejecting the report from UN investigators who concluded that Lubbers' overall behaviour indicated "a pattern of sexual harassment". The secretary-general said legal experts told him the allegations could not be sustained a point he acknowledged in accepting Lubber's resignation.

Nonetheless, Annan said in a statement late Sunday from his spokesman that "the continuing controversy has made the high commissioner's position impossible".