At least four people have been killed in an explosion in the Pakistani city of Rawalpindi, just a few miles away from the capital Islamabad.
More than a dozen people were wounded in the blast, police said today.
The explosion occurred near a bank and a hotel in a neighbourhood not far from the army’s main headquarters.
Police official Kashif Ayaz said the explosives may have been planted in a vehicle in a car park.
Suspected militants have struck Pakistan several times in recent weeks, killing about 250 people in apparent retaliation for an army offensive in a Taliban stronghold in the north west.
Meanwhile, the UN said today it was stopping long-term development work in north-western Pakistan because of security concerns.
The UN said that applied to Pakistan’s tribal areas and the North West Frontier Province, areas where the Pakistani military has launched operations against militants.
The UN says it will focus on emergency, humanitarian relief, security operations and any other essential operations as advised by the UN secretary general.
UN spokeswoman Amina Kamaal said the organisation was still deciding which programmes will be suspended.
The decision follows a string of recent militant attacks in Pakistan, including a bombing of a UN office in Islamabad that killed five people.
"We have had 11 of our colleagues killed because of the security situation," said Ms Kamaal. "All of the decisions are being made in light of that."
Pakistan’s foreign ministry spokesman Abdul Basit said he would reserve comment until he had a chance to review the UN’s statement.