Hard-line separatist leader and All Parties Hurriyat Conference chairman Syed Ali Shah Geelani was detained by the police in Srinagar on Wednesday.
A group of policemen led by senior officers reached his uptown Hyderpora residence on Wednesday afternoon and took the octogenarian separatist leader into custody.
Geelani, who has been spearheading the violent protests that have rocked the valley in the last few months, was shifted to the nearby police station at Humhama.
Over 69 people have been killed in the ongoing unrest till date.
On Tuesday, Geelani had declared, "The failure to meet our demands would lead to an unimaginable stir as the situation would worsen and New Delhi would repent its decision forever."
His demands include 'recognition by New Delhi of Kashmir being an international dispute, release of detainees, revocation of the Armed Forces Special Powers Act, demilitarisation and punishing those involved in the recent killings and assurances by the prime ministers that no rights violation will take place henceforth'.
Geelani, who had been arrested in June this year under the stringent Public Safety Act, had been released in August.
Jammu and Kashmir Chief Minister Omar Abdullah is expected to meet Prime Minister Manmohan Singh on Wednesday evening and reportedly discuss ways to end the current impasse in the valley.
It has been reported that Abdullah will brief Dr Singh and his senior cabinet colleagues on the situation in the valley and suggest measures to break the deadlock.
Dr Singh has also convened a meeting of the Cabinet Committee on Security to discuss the current crisis prevailing in Kashmir.
The Centre is likely to discuss the Armed Forces Special Powers Act and initiate new steps to break the impasse.
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