ISLAMABAD (Reuters) - Pakistani police raided an opposition party youth rally in the capital on Thursday night and arrested about 40 people ahead of a planned protest that party leader Imran Khan has said would shut down the city, a party spokeswoman said.

The arrests were at a youth meeting of the Pakistan Tehreek-e-Insaf (PTI) party in Islamabad's E-11 district, spokeswoman Anila Khawaja said.

"All of the sudden police arrived and started arresting people," she said.

Early on Thursday, a city order banned all public gatherings ahead of Khan's planned protest set to begin Nov. 2.

(Writing by Kay Johnson; Editing by Toby Chopra)