The wounded persons have been shifted to hospitals.
Emergency has already been imposed in the hospitals.
Police sources told our Quetta correspondent, Hussain Farooq that seven of the injured persons are in critical condition.
Firing also took place between security forces and a group of terrorists on this occasion. IG Balochistan said on suicide bomber was killed by police on gate of the church while other blown himself inside the building.
Law enforcement agencies have besieged the area.
President Mamnoon Hussain and Prime Minister Shahid Khaqan Abbasi have strongly condemned the terrorist attack on a Church in Quetta .
In their separate statements, they prayed for the departed souls and expressed sympathies with the bereaved families.
The President said these cowardly attacks cannot shake our resolve to fight the menace of terrorism.
Prime Minister Shahid Khaqan Abbasi has said the whole nation stands united against terrorism and is determined to eradicate terrorism from the country.
Condemning the terrorist attack, he appreciated the timely and effective response by the security forces.
He expressed sympathy with the bereaved families and deep grief and sorrow over the loss of precious lives in the attack.
He also prayed for early recovery of the injured.
Meanwhile Chief of Army Staff General Qamar Javed Bajwa while condemning Quetta church attack targeting our brotherly Christian Pakistanis has said that it is an attempt to cloud Christmas celebrations and create religious cleavages.
He said effective response by Law Enforcement Agencies is commendable and the nation stays united and steadfast to respond against such heinous attempts.
Interior Minister Ahsan Iqbal has also condemned the terrorist attack.
He said anti-state elements want to spread violence in the country but we will continue war against terrorism till the complete eradication of such elements from the country.
The Minister said Islam teaches us respect of minorities and their places of worship.
He said the protection of religious freedom of minorities is duty of the whole nation.
Minister of State for Information and Broadcasting Marriyum Aurangzeb has also condemned the terrorist attack on church in Quetta .
Expressing condolences to the bereaved families, she said the terrorists will be fought till the last of them is flushed out of the country.
She said the terrorists want to impede the development of the country but they will be defeated with courage and determination as the whole nation stands united against them.
Federal Minister for defence Engineer Khurram Dastgir Khan while condemning the suicide attack on the church in Quetta expressed deep grief at the loss of innocent lives.
In his condemnation message, he said Pakistan’s resolve against terrorism cannot be deterred by these cowardly acts.
Governor Balochistan Muhammad Khan Achakzai and Chief Minister, Sardar Sanaullah Zehri have also condemned the bomb explosion.
They have directed health authorities to provide best medical treatment to the wounded persons.