People and rescuers gather outside a church after a suicide attack in Lahore March 15, 2015.[Photo/Agencies]

Prime Minister Nawaz Sharif condemned the attack and asked authorities to beef up the security of churches, mosques and other worship places across the country.

The Pakistan Christian Community announced a three-day mourning for the victims.

Chief Minister of Punjab province Shahbaz Sharif ordered hospitals to provide best possible medical treatment to the wounded.

Bishop of Pakistan Sadiq Daniel, who also condemned the bloody attacks, asked all missionary schools to remain closed on Monday. 

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.