Velappan, the general secretary of the Asian Football Confederation, said he was sorry if he had hurt the feelings of fans for comments made in the wake of Saturday's opening match in Beijing played in front of a half-empty stadium.

The veteran official was outraged after fans booed speeches by guests at the match, threatening to bar future AFC events from the Chinese capital and even suggesting the city was not a suitable venue for the Olympics.

But on Monday Velappan said he accepted an explanation that a technical glitch with the Workers Stadium sound system had created the impression fans were jeering and hissing at guests.

"The fans told me there was a technical problem caused by a time delay. I said I misunderstood why they were booing," said Velappan, who met protesting fans demanding an apology at his hotel on Sunday.

"I said if I hurt your feelings, I apologise," said Velappan, stating that he had no doubts Beijing would host a successful Olympics.

"The Beijing Olympics will be the best ever given the will of the people and the government, it will be really fantastic."

But Velappan stood by his comments over the disappointing turnout in Beijing, saying that he told Chinese fans when meeting them on Sunday that the vast swathes of empty seats created a bad image.

"I said that on Saturday the opening ceremony and the match was televised to more than 100 countries worldwide. And what did people see? A half-empty stadium. Is that negative or positive?" Velappan said.

Velappan's withering post-match tirade attracted blanket coverage in local newspapers here Monday, with all of Beijing's major newspapers carrying front-page stories on the controversy.

Beijing Football Association secretary general Zhang Heng had demanded an apology in an open letter, saying Velappan's criticisms were unfair.

"After the opening ceremony, we were very happy. We think we offered a very good opening ceremony," Zhang said.

"But just at that time, after the match between China and Bahrain, Velappan spoke some words which went beyond the Asian Cup. They harmed the feelings of Beijing people.

"Surely, even if the opening ceremony and what we have done for the Asian Cup is not perfect, this is not a reason for Velappan to doubt if Beijing is capable of holding the Olympic Games.

"Myself, I am a good friend of Velappan but I have to say that his comments are wrong.

"As the secretary of the Beijing organising committee, I demand Velappan explain himself and apologise to Beijing football fans and football people."

Fans were equally outraged and penned their own letter which three representatives handed to Velappan on Sunday.

"We cannot understand why you have made such comments," the letter said.

"These words are irresponsible and Beijing football fans were shocked. We are shocked and indignant.

"Your claim that Beijing is not capable of holding the Olympics harmed, seriously, our feelings.

A spokeswoman for the Asian Cup local organising committee Sunday said fans had not been booing the opening ceremony guests, who included FIFA President Sepp Blatter.

"The football fans were warm and polite," said spokeswoman Wang Hui. "The audio system for the big screen had some technical problems. The sound was delayed by 10 seconds.

"When Blatter and Velappan and other senior officials entered the stadium, the hissing and booing that they heard were not aimed at them," she said.

The booing was apparently aimed at unpopular officials of the China Football Association, the newspapers said Monday.