A young clerk with no knowledge of the 1989 Tiananmen Square crackdown allowed a tribute to victims slip into the classified ads page of a newspaper in southwest China, a Hong Kong daily reported on Wednesday.

Officials at the Chengdu Evening News refused to answer questions about an advertisement it ran saluting the mothers of those killed in a bloody military crackdown on democracy activists at Tiananmen Square in 1989.

The one-line ad on Monday night read: “Paying tribute to the strong mothers of June 4 victims.” It appeared on page 14 of the paper on Monday, the 18th anniversary of the violent end to a seven-week pro-democracy movement.