KABUL (AFP) - - A suicide bomber rammed an explosives-filled car into the gates of the Indian embassy in Afghanistan on Monday, killing more than 40 people including four Indian nationals, officials said.

The blast in the heart of Kabul scattered human flesh and severed limbs outside the embassy of India, one of Afghanistan's staunchest allies as the war-torn country battles an increasingly bloody Taliban insurgency.

A spokesman for the hardliners however denied the Taliban were involved in the attack, the deadliest in Kabul since the insurgency began after the Taliban regime was removed in a US-led invasion in late 2001.

"We have not done this," spokesman Zabihullah Mujahid said.

Indian ambassador Jayan Prasad, who was not hurt in the attack, confirmed to AFP reports that four Indian nationals were among the dead.

The Indian foreign ministry in New Delhi said meanwhile that two Indian paramilitary troopers guarding the embassy were killed in what the Afghan interior ministry said was a suicide car bombing.

"We are walking on rubble," a senior embassy official told AFP soon after the blast. "The embassy has been blown up badly, the outer structures," he said on condition of anonymity.

Reporters were held back from the scene but an AFP correspondent saw a mound of rubble at the gate of the facility, which is close to the interior ministry.

The powerful morning rush-hour blast sent a plume of brown smoke into the air and could be heard across the city centre. It shattered the windows of shops several hundred metres (yards) away, the correspondent said.

"Initial reports indicate that about 40 people, mostly civilians who had come here for visas, have been killed," interior ministry spokesman Najib Nikzad told reporters near the scene.

"More than 40 people, mostly civilians, have been killed," he reiterated to an AFP reporter separately. About 10 Afghan police officers in charge of embassy security were among the dead and wounded, he said.

Health ministry spokesman Abdullah Fahim said earlier hospitals had reported they had 28 bodies and had treated 141 wounded.

Afghan Foreign Minister Rangeen Dadfar Spanta visited the embassy soon after the attack to show support, his spokesman Sultan Ahmad Baheen said.

"The enemies of Afghanistan and India's relationship cannot hamper our relationship by conducting such attacks," Baheen told AFP.

India has provided significant support to Afghanistan's efforts to restore order after the ouster of the Islamic extremist Taliban movement, which seized power in 1996 until they were pushed out.

"Such acts of terror will not deter us from fulfilling our commitments to the government and people of Afghanistan," the Indian government said in a statement condemning the attack.

Since being ousted from power after refusing to hand over Osama bin Laden in the wake of the September 11 attacks, the Taliban have waged a deadly campaign to try to undermine the Afghan government.

Targets have included international and US-led coalition troops from the tens of thousands of foreign forces trying to help President Hamid Karzai restore stability, but attacks have been increasing in Kabul itself.

One of the most daring in the city was on April 27, when militants opened fire on President Karzai as he was about to address the country's largest annual military parade.

A parliamentarian and two other other Afghans were killed, but the president was unhurt.

The international community has sent about 70,000 troops to Afghanistan to help them fight the militants but the insurgency has only gained pace, notably over the past two years.

In other violence Monday, a Canadian soldier died after being badly hurt in a bomb blast in the southern province of Kandahar, a Canadian commander said.

A roadside bomb similar to those used by the Taliban killed three Afghan police in the same province and a separate one killed four more in the neighbouring province of Uruzgan, government officials said.