Pakistani officials have ordered the detention of a firebrand cleric linked to the 2008 Mumbai terror attacks which killed 166 people.

Hafiz Saeed - who led the banned Lashkar-e-Taiba (LeT) militant group and has a $10m (£5.8m) US bounty on his head - is under house arrest in Lahore.

He has repeatedly denied involvement in the Mumbai attacks.

But Delhi and Washington both believe he masterminded the shooting and bombing massacre.

A spokesman for Mr Saeed claimed the Pakistani government had been pressured by the US to act against him.

Mr Saeed heads Jamaat-ud-Dawa (JuD), a Pakistani charity group which India and the US say is a front for the LeT. It is listed as a terror outfit by the United Nations, and was put on a Pakistani terror watch list in 2015.

Four JuD members have also been placed in "preventative detention", according to an order by the interior ministry.

Tensions over Mumbai massacre

The Islamist leader's free movement in Pakistan has been a source of tension between Islamabad and Delhi for years, but it is unclear why the authorities decided to move against him now.

He was put under house arrest in 2008 after the bloodshed in Mumbai, but released about six months later. Pakistan maintained there was not enough evidence to put him on trial or hand him over to India.

The Mumbai carnage played out on live television as commandos battled the heavily armed attackers, who arrived by sea on the evening of 26 November, 2008.

The 10 gunmen killed commuters, tourists, and some of India's wealthy elite in a rampage that included attacks on two luxury hotels, a Jewish centre, and a train station.

It took the authorities three days to regain full control of the city.

Delhi believes there is evidence that "official agencies" in Pakistan were involved in plotting the attack - a charge Islamabad denies.

'US pressure'

Despite the bounty against him, Mr Saeed has led a high-profile public life in Pakistan, regularly delivering fierce anti-India speeches.

In a 2014 interview with the BBC, Mr Saeed said the US was only targeting his organisation to win India's help in Afghanistan.

News of the cleric's detention surfaced hours after Interior Minister Chaudhry Nisar hinted at an imminent crackdown.

He told reporters in Islamabad that Pakistan is "under obligation to take some action" as JuD is blacklisted internationally and has been under observation for years.

"The situation will be clear on this by tomorrow," he said on Monday.

A senior Pakistani defence ministry official told Reuters that Islamabad had not heard anything from President Trump's administration, but had been feeling US pressure over the terror suspect.

"Trump is taking hard decisions against Muslim countries, there is open talk of actions against Pakistan also. So yes, this was a consideration," said the official.