KABUL: At least 30 people were killed and hundreds wounded when a Taliban truck bomb tore through central Kabul and a fierce firefight broke out Tuesday, a week after the insurgents launched their annual spring offensive.

The Taliban claimed responsibility for the attack in a densely crowded neighbourhood, which sent clouds of acrid smoke billowing into the sky and rattled windows several kilometres away.

The brazen assault in a densely packed neighbourhood marks the first major Taliban attack in the Afghan capital since the insurgents announced the start of this year's fighting season.

"(We) condemn in the strongest terms the terrorist attack in Puli Mahmood Khan neighbourhood of Kabul, as a result of which many of our countrymen were martyred and wounded," Ghani said in a statement without specifying the number.

The Afghan health ministry said at least 320 wounded people were rushed to hospital.

"Such cowardly terrorist attacks will not weaken the will and determination of Afghan security forces to fight against terrorism," Ghani said.

Taliban spokesman Zabihullah Mujahid claimed their fighters had managed to enter the offices of the National Directorate of Security (NDS), the main spy agency.

Afghan officials did not confirm that claim but intense gun battles could be heard near the NDS compound.

The Taliban are generally known to exaggerate battlefield claims.

"The first blast was carried out by a suicide bomber in a car and possibly one or two bombers are still resisting,” interior ministry spokesman Sediq Sediqqi told AFP.

"The scene of the attack has been completely cordoned off by Afghan security forces."

Pakistan's Foreign Office also condemned the attack.

UN chief condemns Taliban attack

UN chief Ban Ki-moon strongly condemned the Taliban suicide truck bombing.

“I would like to express my deepest condolences for the victims and their families and friends,” the UN secretary general said at a press conference during a visit to The Hague.

“I condemn strongly these terrorist attacks,” he said, adding “there's no justification whatsoever (for) attacking civilian people as well as security people.”

“We must fight against these terrorist attacks and the international community must be united in working together,” Ban said, speaking alongside Dutch Foreign Minister Bert Koenders.

'Spring offensive'

The Taliban on Tuesday last week announced the start of their "spring offensive" even as the government in Kabul seeks to bring them back to the negotiating table to end the drawn-out conflict.

The Taliban warned they would "employ large-scale attacks on enemy positions across the country" during the offensive dubbed Operation Omari in honour of the movement's late founder Mullah Omar, whose death was announced last year.

The insurgents began the fighting season last week by targeting the northern city of Kunduz, which they briefly captured last year in a stunning setback for Afghan forces.

But officials said Afghan security forces drove Taliban fighters back from the city on Friday.

The annual spring offensive normally marks the start of the "fighting season", though this past winter the lull was shorter and rebels continued to battle government forces, albeit with less intensity.

The Taliban's resurgence has raised serious questions about Afghan forces' capacity to hold their own. An estimated 5,500 troops were killed last year, the worst-ever toll.

Peace talks which began last summer were abruptly halted after it was revealed that Taliban leader Mullah Omar had been dead for two years, a disclosure which sparked infighting in the insurgents' ranks.

A four-country group comprising Afghanistan, the United States, China and Pakistan has been holding meetings since January aimed at jump-starting negotiations.