Omar, seen here with a group of visitors, had called for more effort in the war against the Taliban in the north [AFP]

The governor of Kunduz province has been killed along with more than a dozen other people in a huge explosion at a mosque in northern Afghanistan, according to an Afghan official.

Mohammad Omar, the Kunduz governor, was inside the mosque at the time of the blast, said Abdul Jabar Taqwa, the governor of Takhar province, where the attack occurred.

The blast occurred during Friday prayers at the Shirkat mosque in Taluqan, the main city of Takhar, where Omar had reportedly travelled to because of security concerns in Kunduz.

Omar may have been the target of the attack, Taqwa said.

"We believe a bomb was set up in the mosque to kill the governor," he told the Associated Press news agency. "This is a big loss for us because Mohammad Omar was a very brave and good governor."

AP said a total of 19 worshippers besides the governor were killed in the blast, while 35 people were wounded.

Previous assassination attempts

Al Jazeera's Sue Turton, reporting from Kabul, said Omar had been the target of several previous attempted attacks in the past.

"This is not the first time an assassination attempt has been tried on the governor of Kunduz," she said.

"There were numerous attempts, one only one and a half months ago. And his brother was assassinated a few months ago in Kunduz."

She said the situation in Kunduz had deteriorated in the last few months.

"[Omar] among others had been calling repeatedly for more effort to be put into the north to try to combat the Taliban and [what he said were] al-Qaeda fighters coming across from Uzbekistan and Tajikistan, bolstering the Taliban in that region," our correspondent said.

"Just the day before yesterday, he announced that after this current push in the south in Kandahar, coalition and Afghan forces were going to be moving up for a push in Kunduz province."

Kunduz is a major transportation hub and lies along a crucial supply line for coalition forces that has been repeatedly attacked by Taliban fighters.

Fighters have stepped up attacks on police and civilians in Kunduz in an apparent attempt to destabilise local authorities.