Pakistani authorities have opened a criminal case against leaders of jailed ex-prime minister Nawaz Sharif's political party under an anti-terrorism law, 10 days before a hotly contested general election, according to a police report.

The case relates to a march staged by the Pakistan Muslim League-Nawaz on July 13 when Sharif returned to Pakistan to be arrested on a corruption conviction, which defied a ban on holding public rallies on a Friday.
A copy of the First Information Report (FIR), which marks the formal opening of a criminal investigation, names PML-N party leader Shehbaz Sharif, who is Nawaz Sharif's brother, and a number of other key figures.
The FIR cites section 7 of the Anti-Terrorism Act, which has broad provisions defining terrorism to include creating public fear, and lists 10 alleged violations of ordinary criminal law including unlawful assembly.
"We are taking action against PML-N leaders," the caretaker home minister of Punjab, Shaukat Javed, told Reuters. "But no one will be arrested before the elections."

He said including the terrorism charges was a "mistake" that would be corrected later.
Shehbaz Sharif led Friday's march across the city of Lahore, in which tens of thousands of people took part, intending to send a message to rivals that the popular vote is still with the PML-N ahead of the July 25 election.
Nawaz Sharif and his daughter Maryam were arrested minutes after landing on Friday.
National polls indicate a close race between the ruling PML-N and the Pakistan Tehreek-e-Insaf (PTI, or Pakistan Justice Movement) led by former cricket star Imran Khan, with the Pakistan Peoples Party in third place.
Sharif, who was removed from office by the Supreme Court last year and sentenced to 10 years in prison for "corrupt practices" this month, alleges the military is aiding a "judicial witch-hunt" to prevent the PML-N from winning a second term.
The party's past five years in government have been characterised by discord with the military, which has ruled Pakistan for nearly half its 71-year history.

The Sharifs' return could shake up an election riven by accusations the military is working behind the scenes to skew the contest in favour of Khan, who describes Sharif as a "criminal" deserving no support.
Musadik Malik, a senior PML-N official and member of Senate, said the FIRs are part of a pattern that included pressuring candidates to change to PTI and corruption cases against other party leaders.
"This FIR is just another attempt of intimidation and political victimisation," Malik said.
Malik said the PML-N rally was overwhelmingly peaceful and any ban on gatherings so close to the election was unfair.