Image copyright AP Image caption Geo TV staff have staged regular rallies against what they call the authorities' heavy-handed treatment

Pakistan's Electronic Media Regularity Authority has suspended the licence of the country's largest and most influential TV station for 15 days.

Since April, the Geo TV channel has been embroiled in a defamation row with the powerful ISI intelligence agency.

The ISI says the channel has unfairly linked the agency to an attack on a Geo talk show host in Karachi.

But officials from Geo, Pakistan's most watched news channel, have described the licence suspension as unfair.

Supporters of the channel say the suspension is a dark day for media freedom in Pakistan.

Correspondents note that the allegations against the intelligence agency are unusual because few dare upset the ISI - long regarded as one of the most powerful institutions in the country.

Off air

Geo TV in the news Began broadcasting in 2002, owned by the Independent Media Corporation

Is Pakistan's most-watched television channel

Has the country's largest newsgathering network

Has frequently clashed with the authorities

Angered the ISI with its coverage of the shooting of Hamid Mir in April

Caused further ire by broadcasting a dance routine denounced as blasphemous Battle for Geo TV

In a statement, the Pakistani Electronic Media Regularity Authority (Pemra) said that they had made the decision following a complaint against Geo TV filed by the defence ministry.

Pemra said it "took a strong notice of violations committed" by the channel and "unanimously decided" immediately to suspend its licence in addition to imposing a 10m Pakistani rupees ($100,000) fine.

It added that if the fine was not paid before the end of the suspension period, the channel would remain off air.

The regulators also warned that if there were more violations, "proceedings for the revocation of [Geo's] licence shall be initiated".

Image copyright AFP Image caption Mr Mir - the first journalist to interview Osama bin Laden after the 9/11 attacks - is still recovering from his injuries

Image copyright AFP Image caption Critics of Geo TV accuse the channel of unfairly singling out the ISI as being linked with the attack on Mr Mir

Image copyright AFP Image caption Geo TV is one of Pakistan's largest and most influential television channels

Geo argues that it has already publicly apologised to the ISI for its coverage in the aftermath of the shooting of Hamid Mir, one of Pakistan's best known TV presenters.

He was hit six times in the abdomen and legs after his car was fired on by men on motorbikes as he was leaving Karachi airport in April.

It remains unclear who fired the shots and no group has said it carried out the attack.

Geo added to the ISI's anger when it broadcast images of Islam during interviews with Mr Mir's family who blamed the intelligence agency for the shooting.

Mr Mir himself has also irritated both the ISI and the military by highlighting their alleged role in the abduction of scores of people in the restive south-western province of Balochistan.

Pakistan is one of the word's most dangerous countries for journalists.

In May, a group of Pemra board members had tried to suspend Geo TV's licence on the same issue, but that decision was quickly "disowned" by the regulatory body.