Kabul -  A bomb blast inside a seminary in Parwan province of Afghanistan on Tuesday killed eight children and a senior cleric, Afghan media said.

Deputy governor Shah Wali Shahid said that the head of the Parwan clerical council, Mawlavi Abdul Rahim Hanafi, was assassinated in the explosion.

The explosives were detonated as soon as the students gathered in the classroom. Denouncing the act as a ‘terrorist attack’, Shahid said that Hanafi was the main target of the bombing which occurred at the madrassa in Charakar. He further said that an investigation is underway to determine how the bomb was brought into the classroom.

Officials have claimed that several others too were wounded in the explosion. However, no group has still claimed responsibility for the attack. The Taliban had announced the start of their spring offensive in April, while threatening to step up attacks across the country.

Meanwhile, Afghan security forces are battling Taliban insurgents blocking a main route into the northern city of Kunduz with improvised explosives, officials said on Tuesday, as fears grew local residents could be forced to flee the city.

Heavy fighting has been underway for days around Kunduz, a city that the Taliban have twice come close to capturing in recent years, and government reinforcements included Special Forces units rushed to the province to bolster defences.

"A fight is going on between Afghan forces and the enemy around Kunduz city," said defence ministry spokesman Mohammad Radmanish, adding that three operations were underway. "We have the capacity and enough reinforcements to tackle them," he said.

The heavy fighting, which follows the start of the Taliban's spring offensive last month, has underlined warnings of another difficult year for Afghan forces. They suffered 6,785 killed last year and control only around 60 percent of the country. President Donald Trump is expected to announce an increase in US troop numbers as part of an overall review of United States' strategy in Afghanistan in the coming days.

Officials sought to reassure residents that they had the situation under control, mindful of the chaos that ensued last year when thousands of people fled Kunduz after insurgents seized the town centre. But with fighting coming closer to the city centre, there were growing fears of a repeat."This is the third time that government neglect has left people in fear and terror," said provincial council member Mohammad Yousuf Ayobi by telephone. He said homes, farms and animals had been abandoned by people caught on the front line.

"Fighting is threatening them at any moment," he said. "People in Kunduz are ready to leave the city as soon as they can." Although officials say security forces are pushing back, it was also clear they face a difficult fight with the Taliban, who control much of the countryside around Kunduz and who last week took the district of Qala-i-Zal, just to the northwest of the city on the border with Tajikistan.Mahfouz Akbari, a spokesman for police in eastern Afghanistan, said the insurgents had concentrated much of their strength on Khanabad, another district they control, located on the opposite side of the city to the southeast. "The enemy has planted bombs everywhere and it has caused the operation to go slowly," he said. However he said that most parts of the highway leading from Khanabad into Kunduz had been cleared and districts that had been lost would be retaken.

However there was growing disillusion among local people caught up in yet another round of fighting."I left my village four days ago now," said Noor Mohammad, a resident of Qala-i-Zal, speaking by telephone. "My house is unlocked and my livestock and farm is also left behind. I hope the government can either leave the province to the Taliban or to win full control from the Taliban so we can live here without tension."