Pakistani riot police wielded batons and fired tear gas at stone-throwing opposition activists who rallied in Islamabad in defiance of a government ban on demonstrations on October 28.
There were also skirmishes between supporters of opposition leader Imran Khan and police in the garrison city of Rawalpindi, and in Karachi and Lahore, the capital of the eastern Punjab Province. Police detained dozens of Khan party activists across Pakistan.
The clashes erupted as supporters of Khan's Pakistan Tehrik-e-Insaf opposition party tried to make their way to his residence in the capital for a rally he had called for the previous evening.
The violence prompted Khan, a popular former cricket star, to announce he will defy the ban and go ahead with a planned "million men" march on November 2 in Islamabad to try to force Prime Minister Nawaz Sharif to resign.
Khan said he was not afraid of arrest, and claimed that the government had already placed him under house arrest by stationing police around this residence who have not allowed him to leave.
"Even if you send me to jail, I will come back to lead rallies against you," he said, addressing Sharif.
In Rawalpindi, local Aaj TV said a newborn baby boy suffocated from tear gas during clashes between police and Khan's supporters. The boy's father, railway worker Mohammad Tariq, said their neighborhood got caught up in the clashes and the tear gas made his three-day-old baby choke.
"We rushed to the Benazir hospital but roads were blocked with shipping containers and it took us 90 minutes" to get to the hospital, where the doctor pronounced the baby dead, Tariq told the station.
Police had put the shipping containers in the road to prevent Khan supporters from joining the demonstrations.
WATCH: Crackdown Sparks Protests In Pakistan
Public pressure has mounted on Sharif to step down since his family members were named as holders of offshore bank accounts in leaked documents from the Panamanian law firm Mossack Fonseca.
Sharif, serving his third term as prime minister, has refused to quit and has vowed to prove he and his family did nothing illegal or corrupt.
The Supreme Court has reportedly settled on a panel of judges who will hear the case on Sharif's family offshore accounts next week. Khan's party is one of the five petitioners that asked the court the look into the scandal. The top court has asked Sharif to issue a response to the allegations against him.
Holding offshore companies is not illegal in Pakistan, but Khan has implied the money was gained through corruption. Yet he admitted in May that he used an offshore company himself to legally avoid paying British tax on a London property sale.
The ruling party has dismissed Khan's planned rally, at which he has threatened to shut down the government, as a desperate move by a politician whose popularity is waning ahead of the next general election, likely to be held in May 2018.
"Pakistan is going towards becoming a developed country, and the opposition is worried that if this system of development continues until 2018, then by then their politics will be finished," Sharif told supporters on October 28.
Khan in 2014 held months-long rallies in Islamabad to try to force Sharif to quit and claimed the premier had rigged the 2013 elections. He suspended his party's protests after a Taliban attack in December that year in Peshawar killed 150 people, mostly school children.
With reporting by AP and Reuters