Attacks in the Pakistani cities of Rawalpindi, Quetta and Karachi have left at least 17 people dead and many more injured.
In Rawalpindi, a blast in a Shia Muslim procession killed 10, police said.
Earlier, a bomb outside a Shia mosque in the southern city of Karachi killed at least two people.
And a roadside bomb attack on a military vehicle killed at least three soldiers and two civilians in Quetta, officials said.
The bombings come as Shias celebrate the holy month of Muharram.
No group has so far claimed responsibility for the attacks.
The blast in Rawalpindi reportedly happened as Shias were marching towards a mosque in the centre of the city.
Karachi, where a mosque was apparently targeted, has a long history of sectarian tensions. The attack left seven people wounded, police official Javed Odho told the Associated Press news agency.
Police say the remote-controlled bomb in Quetta exploded near a security vehicle escorting schoolchildren, and about 30 people were wounded, some of them critically.
The city is capital of the south-western province of Balochistan, where a separatist insurgency is being waged by ethnic militants demanding more autonomy and a greater share of natural resources.
Pakistan’s military also has troops in the province engaged in a long-running battle against militants in the tribal areas near the Afghan border, including the Taliban and armed groups who support them.
“The target [of Wednesday’s bomb] was an army vehicle which was escorting a school bus carrying children of local army officers from different schools,” Quetta city police chief Hamid Shakeel told the AFP news agency.
“The device was planted on a motorbike. It exploded soon after the army vehicle came there.”