At least 16 people, including five security personnel, have been killed in two separate attacks in Pakistan's troubled south-western province of Balochistan.
In the first attack, passengers were pulled out of a bus bound for the eastern city of Lahore and shot dead.
Later, gunmen shot a group of labourers in the provincial capital, Quetta.
Officials say Baluch rebels are responsible. No-one has claimed carrying out the attacks.
Baluch rebels have been fighting security forces since 2000, and are demanding complete autonomy and a greater share of resources from the mineral-rich region, says the BBC's Shoaib Hasan in Karachi.
The labourers were returning home from work when gunmen on motor-bikes opened fire on them on Saturday afternoon. All of them died on the spot.
Earlier in the morning, a bus on its way to the eastern city of Lahore was stopped outside Quetta.
Gunmen made all passengers disembark. National identification cards were checked and those from the Punjab province were separated. The rest were released and sent on their way.
A victim now being treated at a local hospital said those held back were lined up. Their captors then opened fire at point-blank range.
Ethnic Punjabis have been regularly targeted by the rebels, who blame Pakistan's Punjabi-dominated army for their troubles.
The rebels had already called for a Baluch boycott of the Independence Day celebrations taking place across Pakistan.
The attacks come a day after insurgents shot dead three policemen in Quetta. Security officials say an operation has now been launched to capture those involved in the killings.