HONG KONG (AP) -- A top Hong Kong official resigned Monday for attending a birthday party with about 200 guests in early January as the city was battling a coronavirus surge.

At least one guests later tested positive. Secretary of Home Affairs Caspar Tsui was among several officials and lawmakers ordered to quarantine after the party, which was held for Witman Hung, a delegate to China's legislature.

Tsui said in a statement issued Monday afternoon that he had not “set the best example during the recent outbreak.” His resignation came as Hong Kong leader Carrie Lam reproached officials who attended the party, saying they should “know better”.

At the time of the gathering, health officials had urged the public to avoid large gatherings to prevent the spread of the virus.

“I made the wrong decision to attend a banquet on January 3 and behaved in an inappropriate manner when all efforts should have been devoted to controlling the spread of the virus,” Tsui said.

“I will take responsibility for my actions, and I have therefore decided to resign from the position of Secretary for Home Affairs.”

Tsui's announcement came hours ahead of a news conference by Lam, who announced the results of a disciplinary probe into officials who had attended the party.

“His conduct has brought the Hong Kong government into disrepute and he and his actions have caused a negative perception by the general public in relation to the conduct of principal officials,” Lam said.

According to the authorities, Tsui did not use the government's contact tracing app when entering the restaurant, which is currently mandatory under coronavirus regulations. He also failed to wear a mask when talking to people, despite rules that stipulate masks should be worn when not eating or drinking.

“These officials should observe the highest standards of personal conduct and integrity at all times,” Lam added.

She said that she had accepted Tsui's resignation as “the right thing to do” as Tsui had taken responsibility for his actions.

Two other civil servants will also receive verbal warnings for their actions. One of them was deemed to have stayed too long at the party, outside of an official capacity. The other received a warning for reporting to work a day after he received a mandatory testing notice and putting his colleagues at risk.

In January, Lam expressed disappointment at the behavior of the officials and lawmakers who attended, and ordered those in quarantine to be suspended from their duties.