In the wake of tens of thousands of demonstrating Islamists were swept away from Bangladesh capital's key commercial district and at least 20 have been killed, Prime Minister Sheikh Hasina's state machinery on early Monday closed down two popular pro-opposition TV channels.

The opposition Diganta Television and Islamic Television were blacked out at around 4:27 a.m. and about 2:30 a.m. local time respectively.

"A team of Bangladesh Telecommunication Regulatory Commission ( BTRC) conducted a drive at our office and suspended broadcasting," Imran Ansary, a senior reporter of a TV channel, told Xinhua.

"The BTRC officials informed us that the government issued an executive order to suspend Diganta's broadcast temporarily," he said, quoting the BTRC team leader.

Islamic Television journalist Syed Atik told Xinhua that "a group of 20-30 people forcibly entered our office at about 2:30 a. m. and locked the rooms from where we broadcast programs."

He could not tell whether they were officials from relevant authorities like BTRC.

Both Diganta and Islamic are well known TV channels of the Bangladesh Jamaat-e-Islami party, a key ally in ex-prime minister Khaleda Zia's 18-party opposition alliance.

The BTRC spokesman could not be reached immediately for comment.

Last month Mahmudur Rahman, acting editor of the Bengali- language Daily Amardesh and one of the government's most vocal critics, was sent to jail. Later the authorities of the daily have suspended publication of the newspaper as the government also sealed off its printing press.

In protest against the closure of the TV channel, Ansary said hundreds of journalists have staged demonstration in Dhaka's National Press Club though police banned all sorts of public assembly in the capital city from 11 a.m. to midnight amidst rising tension following clashes between supporters of Hefazat-e- Islam, a group of non-political Islamic scholars who draw support from thousands of people across Bangladesh, and security forces.

At least 20 people including one police man and two paramilitary troops have reportedly been killed on Monday as demonstrating Islamists were swept away from Dhaka's commercial district.

During the more-than-one-hour drive amid a blackout in the early hours of Monday with about 10,000 law enforcers, television footages showed armored vans driving about and non-stop teargas shells being lobbed and rubber bullets fired.

Hours after deadly clashes between Islamists and law enforcers that had left at least four dead and over 100 injured on Sunday, Bangladesh's ruling party asked hundreds of thousands of protesters of a Islamic group to "leave Dhaka by evening or face stern action."

The Islamists under the banner of Hefazat-e-Islam were marching towards their rally venue in Dhaka's commercial district Motijheel after they besieged the capital city to press home their 13-point demands which include mainly enactment of an anti-blasphemy law.

Thousands of anti-riot police and ruling party men are seen in the streets of Dhaka as situation still remains tense in parts of the city and elsewhere in the country.

The raid has not been officially announced yet.