ISLAMABAD, Pakistan — Authorities arrested two more alleged terrorists yesterday in connection with the recent assassination of a former prime minister, Benazir Bhutto.

The arrests took place in Pakistan’s mountainous North-West Frontier Province, where a teenage suspect and a man identified as his handler were taken into custody two days earlier.

One of those arrested Sunday was identified as Mohammed Akram, from the Mansehra district. Authorities said videotape taken on the day Bhutto was slain showed Mr. Akram standing in front of her vehicle moments before she was killed, an investigator who asked not to be identified said. However, a spokesman for the Pakistani Interior Ministry denied that any suspects had been taken into custody yesterday.

It was not clear what Mr. Akram was doing that caused him to become a suspect. Police did not release any information on the second man arrested yesterday.

The investigator said police had reviewed videos of the event and were looking for anyone who was in front of Bhutto’s vehicle before the shots were fired.

Saturday, police arrested a teenager they said told them he would have been the next suicide bomber sent to target Bhutto had she survived the December 27 attack.

The teenager, Aitzaz Shah, and another suspect, Sher Zaman, identified as Mr. Shah’s handler, were transferred to Islamabad yesterday for further interrogation.

Also yesterday, police searched Shah’s home in Single Kot village in the Mansehra district, but it was not clear whether they uncovered any additional evidence.

Elsewhere, violence erupted across Pakistan’s mountainous border with Afghanistan yesterday as thousands marked the Ashoura holiday, when Shiite Muslims mourn the death of Imam Hussein, grandson of the prophet Muhammad.