Protests were planned in Pakistan's major cities Tuesday after authorities detained one of the alleged masterminds of the 2008 Mumbai attacks after years of pressure to act against his group.

Firebrand cleric Hafiz Saeed, who heads the Jamaat-ud-Dawa (JuD) group and has a $10 million US bounty on his head, is to be placed under ‘preventative detention’, according to an order from the interior ministry.

Police took Saeed away from a mosque in Lahore late Monday and escorted him to his residence where they appear to be holding him under house arrest, an AFP journalist reported.

‘My detention orders are unlawful and we will challenge them in the court,’ Saeed told reporters before he was led away by police.

‘These orders have come from Washington,’ he claimed.

JuD, listed as a terror outfit by the United Nations, is considered by the US and India to be a front for Lashkar-e-Taiba (LeT), the militant group blamed for the attack on India's financial capital.

Saeed is believed by the US State Department to be one of the masterminds of the attack.

There has not yet been any reaction from either India or the US to Saeed's detention.

JuD organisers told AFP Tuesday that protests were planned in major cities including Islamabad, Karachi and Lahore. A spokesman for the group, Nadeem Awan, confirmed the detention order would be challenged in court.

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

It took the authorities three days to regain full control of the city and New Delhi has long said there is evidence that ‘official agencies’ in Pakistan were involved in plotting the attack.

Islamabad denies the charge.

But for years JuD operated freely across the country, popular for its charity work especially in the wake of natural disasters, and despite the bounty Saeed led a high-profile public life, regularly delivering fiery anti-India speeches.

India has long seethed at Pakistan's failure either to hand over or prosecute those accused of planning the Mumbai attacks, while Pakistan has alleged that India failed to give it crucial evidence.

It was unclear why Pakistan chose to take action now.

The detention order placed JuD and a foundation tied to it on a watch list, and also ordered the detention of four other members.

As he was escorted away by police Monday Saeed vowed his movement would continue ‘until Kashmir's independence’.

Pakistan and India both control part of Kashmir but claim it in full, and have fought two of their three wars over the territory.

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