ISLAMABAD - Bombs outside two churches in the Pakistani city of Lahore killed five people and wounded more than 40 during Sunday services, rescue workers said, and witnesses said quick action by a security guard prevented many more deaths.

A Pakistani Taliban splinter group claimed responsibility.

The blasts in a majority Christian suburb of the eastern city went off minutes apart. Police said it seemed that the blasts targeted two churches, one Catholic and one Protestant, that are very close to each other.

"I was sitting at a shop near the church when a blast jolted the area. I rushed towards the spot and saw the security guard scuffle with a man who was trying to enter the church, after failing, he blew himself up," said witness Amir Masih.

"I saw his body parts flying through the air."

The guard died as well, he said. It was not clear if the first blast was also a suicide bomber, Masih said.

Rescue services spokesman Sajjad Hussain said five people had been killed and more than 40 people injured.

"The rescue operation is still underway and the death toll may increase," he said.

Taliban splinter group Jamaat-ul-Ahrar claimed responsibility for the blasts.

Lahore is the capital of Punjab, Pakistan's wealthiest and most populous province and the political heartland of Prime Minister Nawaz Sharif.

The city is generally considered peaceful compared with many other areas of Pakistan, but violence there has been increasing after the government's failed attempts to hold peace talks with the Taliban last year.

After the talks failed, the military launched an offensive in the remote northwestern region of North Waziristan along the Afghan border to push the Taliban from the last major region they controlled.

The military now holds the major urban centres there, but residents say many militants fled before the offensive began and others remain in rural areas.