PESHAWAR, Pakistan — A suicide attack killed at least four people and injured 20 others in Pakistan's southwestern province of Baluchistan early Sunday, officials in the country said.
A convoy of the paramilitary Frontier Corps was targeted as it was changing duty at a security post, Azhar Akram, a senior police officer in Baluchistan's capital, Quetta, said at a news conference.
He said the attacker used a motorcycle to get near the paramilitary force, which is in overall charge of security in Baluchistan, a restive province in northwest Pakistan that borders Afghanistan's south.
More than 13 pounds of explosives were used, he said, adding that body parts were found at a distance from the security post.

The militant group Tehreek-e-Taliban Pakistan, or TTP, also known as the Pakistani Taliban, claimed responsibility. The TTP is a separate organization from the Taliban in neighboring Afghanistan.
"Our fidaee [suicide bomber] had planted explosives on the motorbike and rammed into the military convoy in Quetta," TTP spokesman Mohammad Khurasani said from an undisclosed location Sunday. "The security forces were about to leave for patrolling when they were attacked."
Pakistani Prime Minister Imran Khan condemned the attack on Twitter.
"My condolences go to the families of the martyrs & prayers for the recovery of the injured," Khan said. "Salute our security forces & their sacrifices to keep us safe by thwarting foreign-backed terrorists' designs."
The attack comes just weeks after the Afghan Taliban marched unopposed into Afghanistan's capital, Kabul, without firing a shot.
The TTP renewed its allegiance to the Afghan Taliban as they pushed out the Western-backed government and has recently stepped up its campaign against the Pakistani army.
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Islamabad fears a rise in militant attacks along the Afghan-Pakistan border as the Afghan Taliban tries to fill a vacuum left by the collapse of the Afghan government.
However, the Afghan Taliban's leaders have given reassurances to their neighbors and other countries that their territory will not be used to plan attacks on foreign soil.
There was no immediate reaction to the attack from the Taliban leadership in Afghanistan, which is expected to form a new government this week.
Mushtaq Yusufzai reported from Peshawar. Yuliya Talmazan reported from London.