Authorities in northwestern Pakistan say at least 15 people were killed and more than 35 others wounded late Saturday when two blasts ripped through the city of Peshawar, the capital of Khyber Pakhtunkhwa province.

The Associated Press quoted a senior police officer in Peshawar, Dost Mohammed, as saying the first smaller blast drew rescue workers and police to the site. A few minutes later, a large explosion rocked the area, causing all the casualties.

The nature of the blasts is not known and no one has claimed responsibility.