UTHAI SAWAN, Oct 9 (AFP) — CNN pulled a story on the massacre of Thai preschoolers and apologized Sunday over criticism its journalists entered the day care where the children were slain and filmed the crime scene without permission.

The two CNN journalists involved were fined after authorities found that they had been working in the country after entering on tourist visas, but cleared of wrongdoing for entering the day care center where more than 20 children were killed, deputy national police chief Surachate Hakparn said.

He said his investigation had determined the journalists believed they had obtained permission to enter and film after being waved into the building by a volunteer or a health officer, and were unaware the person was not authorized to allow them inside.

They each agreed to pay fines of 5,000 baht ($133) and leave the country, he said.

Both journalists apologized, as did CNN International's executive vice president and general manager Mike McCarthy.

In a statement, he said his reporters sought permission to enter the building but the team "now understands that these officials were not authorized to grant this permission," adding that it was "never their intention to contravene any rules."

"We deeply regret any distress or offense 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.

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

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 northeastern Thailand, where they were reporting on the Thursday attack by a fired policeman who authorities say 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.

That prompted criticism from the Foreign Correspondents' Club of Thailand, 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 criticized 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 an initial response, CNN tweeted that the crew had entered the premises when the police cordon had been removed from the center, and were told by three public health officials exiting the building that they could film inside.

"The team gathered footage inside the center 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 center to leave."

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.