45 killed in Pakistan bombing

Scores of others are believed to have been injured in the attack, which occurred at a hospital in the Balochistan provincial capital of Quetta.

The bomb exploded at the entrance to the emergency department, where the body of prominent lawyer Bilal Anwar Kasi - who was shot dead earlier on Monday - was being brought.

Gunfire is believed to have followed the attack, but no terrorist group has of yet claimed responsibility for the bombing.

Pakistani police have said they suspect the bomb was detonated by a suicide attacker.

Video footage of the bombing showed dozens of bodies strewn on the ground - some still smoking or on fire - among pools of blood and shattered glass, as shocked survivors cried and comforted one another.

Many of the dead appeared to be have been wearing black suits and ties, and are believed to have been prominent lawyers and journalists who were visiting the hospital to pay their respects to the murdered lawyer.

Officials said mobile phone jammers had been activated around hospitals in the area, which made it difficult to contact officers on the ground, and to confirm official death tolls.

Balochistan health minister Saleh Baloch said: "The last information we had was 40 dead but it may increase."

The military has also been deployed in and around the city's hospitals.

Facebook has activated its safety check for Quetta in the wake of the attack.

The toll makes the attack the second deadliest in Pakistan this year so far, after a bombing in a crowded park in Lahore over Easter killed 75.