A Hong Kong artist who became embroiled in a controversy over a newspaper cartoon that showed riot police being called to a school to handle unruly pupils on Wednesday denied he meant to criticise the force and insisted he only wanted to ask teachers to be more lenient on disciplinary matters.

The row erupted after the force wrote a letter of complaint to Chinese-language newspaper Ming Pao on Tuesday that voiced “strong concern” about what it said was “misleading” content in the cartoon by Zunzi.

The illustration depicted riot police arriving at a school, with one officer asking a bespectacled woman: “What bad things have the students done today, headmistress Chan?” The woman listed the infringements – using foul language, stealing an eraser, bringing along a laser pen, and talking back to the teacher.

Zunzi, whose real name is Wong Kei-kwan, denied he had meant to take police to task, Ming Pao reported.

The cartoonist said he had meant to get across the message that schools should educate children with skill and patience and not resort to high-handed measures.

Ming Pao also said it would continue to provide readers with accurate and reliable news content, and to support staff who provided professional work.

Leung Chun-ying. a former city leader, backs police force over its attack on “misleading” newspaper cartoon.

But the force said readers could connect the cartoon with a news report on an earlier page about 14 pupils at St Francis Xavier’s School in Tsuen Wan who were suspended for three days for showing “disrespect” because they had failed to turn up for a national flag-raising ceremony last week.

The school also called police the same day to report suspicious damage to its front gate.

The police letter, sent to Dominic Lau Chung-yeung, the executive editor-in-chief of Ming Pao on Tuesday, said the cartoon could mislead readers into thinking officers were called in to handle pupils who showed “disrespect” for the flag-raising ceremony.

The letter added the cartoon content’s was “not factual” and would not only “damage the force’s reputation” but also “harm the force’s relations with citizens”.

Former Hong Kong leader Leung Chun-ying also weighed in on the controversy on Wednesday and accused the cartoon of “bending the truth” and seeking to “smear” police and the school.

Leung said in a post on his Facebook page that the cartoon illustrated the need for Hong Kong to step up its “anti-smearing” efforts if it was to “resume normality”.

The Education Bureau has asked St Francis Xavier’s to submit a report on the flag-raising row and also appealed to schools to handle pupils who misbehaved during such ceremonies in a “reasonable, fair and lawful manner”.

Legislator Tang Fei, who is also a vice-chairman of the Federation of Education Workers, said the government should issue guidelines to schools on penalising pupils in cases involving national flags or the anthem, instead of allowing a free hand.