By Shwe Yee Saw Myint and Aung Hla Tun

YANGON (Reuters) - Police on Friday detained the chief executive and the chief editor of Myanmar's largest daily newspaper over a defamation case by a powerful politician following a Facebook posting.

The police detained Than Htut Aung, the flamboyant chief executive of Eleven Media Group and the newspaper's chief editor, Wai Phyo, after Yangon's regional government sued them for defamation over a social media post alleging corruption.

The two have been charged under Myanmar's controversial telecommunication law, which human rights monitors have criticized as being too broadly worded.

The law prohibits use of the telecoms network to "extort, threaten, obstruct, defame, disturb, inappropriately influence or intimidate".

Rights monitors have raised concerns over media freedom in Myanmar after a journalist at an English-language newspaper said she was fired following government criticism of her reporting on a crisis in Myanmar's restive Rakhine state.

The two journalists were summoned to the police station after the lawsuit was filed over the posting by Than Htut Aung, said Lt-Col. Myint Htwe, the head of the Yangon Eastern District police force.

"Than Htut Aung, the chief executive of Eleven Media Group, and chief editor Wai Phyo came to our station and surrendered themselves at 1 p.m. today," he told Reuters.

The journalists, who followed their newspaper story on Sunday with the Facebook posting adding details the next day, said their information came from two business people, whom they have refused to identify.

The editors and the group's representatives, contacted by telephone on Friday, were not immediately available for comment.

Phyo Min Thein, 47, a former political prisoner and rising star of Nobel peace laureate Aung San Suu Kyi's National League for Democracy (NLD) party, has rejected the allegations as being intended to defame him.

"(The) post was intended to defame my personal dignity, (it's a) misrepresentation and it has disturbed my activities," Phyo Min Thein told a news conference on Thursday.

The two men were transferred on Friday to Yangon's infamous Insein prison and will stay in custody for two weeks, domestic media said.

It is up to the judge handling the case whether to grant them bail, said Ko Ni, one of Myanmar's leading constitutional scholars.

A member of the ruling NLD was charged under the same law in a separate case this month for criticizing the army and the commander-in-chief Min Aung Hlaing.

Arrests of social media users whose posts are deemed distasteful have continued under Suu Kyi's government.

(Reporting by Shwe Yee Saw Myint and Aung Hla Tun; Editing by Clarence Fernandez)