Thai authorities have fined two CNN journalists for working in the country on tourist visas but cleared them of wrongdoing for entering the day care centre where more than 20 children were killed.

Deputy national police chief Surachate Hakparn said the journalists had been waved into the building by a volunteer or a health officer, but did not know the person was not authorised to allow them inside.

They each agreed to pay fines of 5,000 baht (£119) and leave the country after admitting to working despite entering Thailand on tourist visas, he said.

Authorities began looking into the incident after a Thai reporter posted an image on social media of two members of the crew leaving the scene in north-eastern Thailand where a fired policeman on Thursday massacred 36 people, 24 of them children.

One CNN crew member was seen climbing over the low wall and fence around the compound, over police tape, and the other already outside.

Buddhists pray with relatives of the victims of a mass killing attack in front of the Young Children’s Development Centre in the rural town of Uthai Sawan, north-eastern Thailand
A Buddhist ceremony in front of the Young Children’s Development Centre in the rural town of Uthai Sawan (Sakchai Lalit/AP)

CNN tweeted that the crew had entered the premises when the police cordon had been removed from the centre and were told by three public health officials exiting the building that they could film inside.

“The team gathered footage inside the centre for around 15 minutes, then left,” CNN said in its tweet.

“During this time, the cordon had been set back in place, so the team needed to climb over the fence at the centre to leave.”

The tweet came in response to criticism from the Foreign Correspondents’ Club of Thailand (FCCT), which said it was “dismayed” by CNN’s coverage and the decision to film the crime scene inside.

“This was unprofessional and a serious breach of journalistic ethics in crime reporting,” the FCCT said.

The Thai Journalists’ Association criticised CNN’s actions as “unethical” and “insensitive,” and called for an internal company investigation of the incident in addition to the official Thai probe.

In a later statement, CNN International’s executive vice president and general manager Mike McCarthy reiterated that his reporters sought permission to enter the building but the team “now understands that these officials were not authorised to grant this permission”, adding that it was “never their intention to contravene any rules”.

He said CNN had ceased broadcasting the report and had removed the video from its website.

“We deeply regret any distress or offence our report may have caused, and for any inconvenience to the police at such a distressing time for the country,” he said in the statement tweeted by CNN.

As Thailand’s worst such massacre, the attack drew widespread international media attention to the small town of Uthai Sawan in the country’s rural northeast.

By Sunday, few remained but a large number of Thai media continued to report from the scene.