Afghan security forces inspect a damaged vehicle at the site of a bomb attack near the entrance to Kabul's international airport on Monday.

AFP/Kabul

Afghan President Ashraf Ghani accused Pakistan on Monday of sending "messages of war" and harbouring bombmaking camps, after a wave of devastating blasts in Kabul killed at least 56 people.

A Taliban suicide car bomber killed five people on Monday near the entrance of Kabul's international airport, the latest in a barrage of violence that has convulsed the Afghan capital since Friday.

The Taliban are stepping up their summer offensive amid a bitter leadership dispute following the announcement of the death of long-time supremo Mullah Omar.

Since coming to power last year Ghani has actively courted Pakistan, which has historically backed the Taliban, in what experts call a calculated gambit to pressure the militants to the negotiating table.

But in a volte-face on Monday, Ghani slammed Pakistan for failing to rein in the Taliban as peace talks falter and insurgents step up attacks that are a test for beleaguered Afghan security forces.

"The last few days have shown that suicide bomber training camps and bomb-producing factories which are killing our people are as active as before in Pakistan," Ghani told a news conference.

"We hoped for peace but we are receiving messages of war from Pakistan."

In Monday's attack a suicide car bomber tore through a crowd during the lunchtime rush at a checkpoint where passengers undergo the first round of body checks before entering the airport.

Smoke billowed from the scene of the explosion, which killed at least five people, with officials warning that the toll could rise further.

An AFP photographer saw pieces of charred flesh littered around the checkpoint.

Ambulances with wailing sirens rushed to the site and were seen removing bodies from the area, which was strewn with the twisted and mangled wreckage of burning vehicles.

The Taliban said two vehicles belonging to foreign coalition forces were the target.

'Heinous act'  

The Nato mission in Afghanistan has not yet commented on the bombing, which the Afghan interior ministry denounced as a "heinous act, against the values of humanity".

It was the latest in a series of bombings in the city which began on Friday with three blasts - one close to an army complex, one at a police academy and one at a US special forces base - which killed a total of 51 people.

They were the first major attacks since Mullah Akhtar Mansour was named as the new Taliban chief in an acrimonious power transition, after the insurgents confirmed Omar's death.

Some top leaders of the Islamist insurgency, including Omar's son and brother, have refused to pledge allegiance to Mansour, saying the process to select him was rushed and even biased.

Tayeb Agha, the head of the Qatar political office set up in 2013 to ease talks with Kabul, resigned last week in protest at Mansour's appointment and two more members of the office followed suit.

Elsewhere in Afghanistan, a Taliban attack on Sunday killed up to 29 people in the northern province of Kunduz, which has become a key battleground in the fight against the militants.

The wave of violence underscores Afghanistan's volatile security situation amid a foundering peace process.

Pakistan has historically supported the Taliban insurgents and many Afghans accuse it of continuing to nurture militant sanctuaries on its soil in the hope of maintaining influence in Afghanistan.

Ghani's comments on Monday are his strongest yet against it.

"In my telephone call with (Prime Minister Nawaz Sharif on Sunday), I told Pakistan to see terrorism in Afghanistan the same way it sees terrorism in Pakistan," he said.

"I ask the Pakistani government if the mass killings of Shah Shaheed had happened in Islamabad and the perpetrators were in Afghanistan, what would you do?" he said, referring to a Kabul neighbourhood that suffered a fatal truck bombing on Friday.

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