Gunmen kill 43 in a bus in Karachi

At least 43 people were killed and 20 injured when gunmen opened fire inside a bus carrying Ismaili Shia Muslims in the Pakistani port city of Karachi.

The incident took place near the city's Safoora Chowk area in the provincial capital of Sindh.

Sindh Police Inspector General Ghulam Haider Jamali said 60 people were travelling in the bus.

Hospital sources said the victims included 16 women. No children were on board.

An eyewitness said six men riding motorcycles opened fire at the bus. They managed to escape after the incident.

However, video footage of the bus did not show bullet holes on the body of the vehicle suggesting that the attackers entered the bus and fired their guns.

Following the incident, Pakistan Army Chief Gen. Raheel Sharif cancelled his scheduled trip to Sri Lanka where he was to go on Wednesday.

Prime Minister Nawaz Sharif and Sindh Chief Minister Syed Qaim Ali Shah have strongly condemned the incident.

Indian Prime Minister Narendra Modi has also condemned the incident.

"The attack in Karachi is deeply saddening & utterly condemnable. Our thoughts are with the families of the deceased," Modi tweeted.

"We stand firmly with the people of Pakistan in this hour of grief. I wish all those injured quick recovery," he added.