KARACHI: Muttahida Qaumi Movement (MQM) Altaf Hussain was arrested on Tuesday in London on charges of money laundering.
Hussain was being investigated for money laundering worth at least 400,000 pounds as well as for incitement to violence and MQM leader Dr Imran Farooq’s murder.
The Karachi Stock Exchange (KSE-100 index) fell 180 points immediately after the news and commercial centres across Sindh’s provincial capital had started to shut down.
Police in London have arrested the leader of Pakistan’s powerful MQM party, Altaf Hussain, on suspicion of money-laundering.
Live situation of Altaf Hussan arrest
Officers are searching a residential address in north-west London where they say a 60-year-old man was detained.
Mr Hussain has lived in the UK since 1991, saying his life would be at risk if he returned to Pakistan.
His party, which controls Karachi, has urged supporters to stay calm. Police are on alert amid reports of violence.
The British and Pakistan authorities have in the past expressed concerns that any arrest of Altaf Hussain could lead to violent protests in Karachi.
Shootings have been reported from some parts of Pakistan’s largest city, which BBC correspondents say is tense.
Traffic jams were reported in Karachi and other cities in Sindh province as businesses closed and people headed home fearing violence.
One man in the city, who gave his name as Tahir, told the BBC that MQM supporters were firing in the streets and setting fire to any shop which remained open.
Another, Nabil, said there had been “turmoil” and “massive confusion” about whether Altaf Hussain had been arrested or not.