KANDAHAR (AFP) - Five UAE officials were among 57 people killed in a string of bombings across Afghan cities, authorities said on Wednesday (Jan 11), as Taleban militants step up a deadly winter campaign of violence.

The Emiratis were among 12 people killed when explosives hidden in a sofa detonated inside the governor's compound in southern Kandahar on Tuesday (Jan 10), while the UAE's ambassador to Afghanistan escaped the attack with injuries.

Just hours before, twin Taleban blasts in Kabul tore through a parliament annexe, which houses the offices of lawmakers, killing at least 38 people and wounding around 86 others.

And earlier Tuesday (Jan 10), a Taleban suicide bomber killed seven people in Lashkar Gah, the capital of volatile Helmand province, as the militants ramp up nationwide attacks in frigid winter months, when fighting usually wanes.

In a statement issued on Wednesday (Jan 11), Singapore said: "There can be no justification for such a despicable act, particularly against diplomats who were on a humanitarian mission."

"We convey our deepest condolences to the families of the victims and wish those injured a speedy recovery."

The carnage underscores growing insecurity in Afghanistan, where US-backed forces are struggling to combat a resilient Taleban insurgency as well as Al-Qaeda and the Islamic State in Iraq and Syria (ISIS).

Kandahar's governor Humayun Azizi and UAE envoy Juma Mohammed Abdullah Al Kaabi were wounded by flames from the explosion, but many others were burned beyond recognition, said provincial police chief Abdul Raziq, who was present when the blast occurred.

"I was in the room, but had to leave to offer my evening prayer," Mr Raziq said.

"I heard the boom from outside and when I came back I saw people were burning."

Kandahar's deputy governor Abdul Shamsi was among the 12 people killed.

Mr Raziq blamed Pakistan's powerful Inter-Services Intelligence (ISI) and the Taleban-allied Haqqani network for the attack, adding they had long been plotting to eliminate Kandahar's leadership.

"The terrorist attack happened at a time when the ambassador and a number of UAE diplomats in Afghanistan were on a trip to Kandahar to lay the foundation stone of an orphanage," the Afghan foreign ministry said.

UAE President Sheikh Khalifa bin Zayed Al Nahyan ordered three days of mourning "in honour of the martyrs who gave their lives in defence of humanitarian causes", President Ashraf Ghani condemned the bombing and ordered an investigation led by Afghanistan's National Security Council chief Hanif Atmar.

The Taleban denied responsibility for the Kandahar attack, but said they were behind the Kabul blasts.

In the first explosion, a suicide bomber blew himself up next to a minibus transporting government employees. As rescuers reached the scene, a car bomb went off.

Among the 38 dead were five policemen who were killed in the second explosion when they rushed to help the victims of the first blast.

Afghanistan's health ministry warned that the toll was expected to rise as many of the wounded were battling for their lives in hospital.

Relatives of the victims held tearful funerals in Kabul amid seething anger over rising insecurity.

"It is a pity that our youth die in vain every day," said Feraidoon, the relative of a victim who got married three months ago.

"We spend a lifetime to raise our children and terrorists take them away in an instant." .

Condemning the Kabul bombings as a "barbaric attack", Mr Ghani lashed out at the Taleban for killing civilians.

"Such unprincipled, unlawful and deplorable attacks cause immense human suffering and make the peace that Afghans need and deserve even more difficult to achieve," the United Nations Assistance Mission in Afghanistan said in a statement.

Tuesday's (Jan 10) carnage came just ten days before Mr Donald Trump is sworn in as US president.

The situation in Afghanistan will be an urgent matter for the new leader, even though America's longest war got scarcely a passing mention in the bitterly contested presidential election.

Mr Trump has given few details on his expected foreign policy, with even fewer specifics on how he will tackle the war in Afghanistan.

Repeated bids to launch peace negotiations with the Taleban have failed and a fierce new fighting season is expected to kick off in the spring.

Afghanistan last week welcomed the Pentagon's decision to deploy some 300 US Marines to Helmand, where American forces engaged in heated combat until they pulled out in 2014.

The Marines will head to the poppy-growing province this spring to assist a Nato-led mission to train Afghan forces, in the latest sign that foreign forces are increasingly being drawn back into the worsening conflict.

Nato officially ended its combat mission in December 2014, but US forces were granted greater powers in June to strike at the insurgents as President Barack Obama vowed a more aggressive campaign.