CP -- KABUL - A string of attacks across Afghanistan, including one carried out by a suicide bomber pushing an ice cream cart, killed at least 21 people Saturday, officials said, while the U.N. released a report showing May to be the deadliest month for Afghan civilians since 2007.

Violence has been on the rise in recent months as the Taliban and other insurgents try to regain territory lost in the fall and winter to the U.S.-led coalition in southern Afghanistan. The U.N. report found that insurgent attacks were to blame for the vast majority of the civilian deaths last month.

One of Saturday's suicide bombings, in the central province of Ghazni, seemed designed to draw crowds of civilians, especially children, though the insurgency generally focuses its attacks on international and Afghan armed forces.

"The suicide attacker was a young man with a thin beard and moustache wearing a scarf," said a witness who identified himself as Asadullah. "He was pushing an ice cream cart. I was standing just 20 metres from him and then he exploded."

The blast killed one child and wounded three others, said provincial police chief Mohammad Hussain.

The Taliban began its yearly spring offensive on April 30. The month that followed saw the most civilian deaths of any month since the U.N. started closely tracking casualties in 2007.

A United Nations interim report found that 368 civilians were killed in May and 593 were wounded. Previously, the deadliest month was August 2008, with 341 deaths.

The U.N. said insurgents were responsible for 82 per cent of those civilian deaths last month, while 12 per cent were killed by the international alliance and Afghan forces. Homemade bombs, such as a roadside device that struck a minibus in Kandahar on Saturday, were the leading cause of death, according to the report.

NATO airstrikes, a frequent cause of tension between the Afghan government and the alliance, were responsible for 3 per cent of civilian deaths in May, the report found.

Casualty figures blamed on the coalition and Afghan forces have been steadily declining over the past four years — despite a rapid swelling in the number of allied and government forces. A recent U.N. report found that insurgents were responsible for 2,080 deaths in 2010 compared with 440 for the coalition and Afghan troops. That report found that deaths due to airstrikes declined by 52 per cent last year compared with 2009.

The U.N., which is preparing a midyear civilian casualty report for 2011, said it decided to release the interim numbers Saturday because of the high rate of civilian killings in May.

"We are very concerned that civilian suffering will increase even more over the summer fighting season, which historically brings the highest numbers of civilian casualties. Parties to the conflict must increase their efforts to protect civilians now," said Georgette Gagnon, director of human rights for the U.N. mission in Afghanistan.

The worst of Saturday's attacks took place in the Khakrez district of Kandahar province in southern Afghanistan, where a roadside bomb killed all 16 members of a family travelling to a shrine for a religious pilgrimage. The family included eight children, five women and three men who were in a minibus, said provincial police chief Abdul Raziq.

He said the bomb was planted by the Taliban and was intended for NATO or Afghan forces.

In the eastern province of Khost, a suicide bomber blew himself up outside the local police headquarters in the Shai Kali area, killing three policemen and a child, according to provincial police chief Sadar Mohammad Zazai.

Among the dead was a local police chief, Zazai said. It was not immediately clear whether he was specifically targeted. Provincial health director Hedayatullah Hamidi said 25 people were wounded in that attack.

President Hamid Karzai condemned the bombings.

"All Afghans want peace and stability in their country and none of these cruel and inhuman actions will stop the aim of peace," he said.

The insurgency has focused on Afghan security forces in a bid to undermine training and recruitment efforts of the international coalition, which hopes to transition security to the nascent Afghan force in targeted areas.

Security along Afghanistan's border with Pakistan has been fraught, with Taliban fighters filtering in from Pakistan to stage spectacular attacks in the eastern part of the country.

NATO announced that a service member died as a result of an insurgent attack in southern Afghanistan. NATO did not release any other details about the death. The killing brings the total deaths this month to 23. Since the start of the year, 229 have died.

Separately, France identified two of its soldiers who died on Saturday.

France's Defence Ministry said a lieutenant died from injuries sustained when a Gazelle light helicopter crashed in bad weather not far from the Bagram Air Base north of Kabul. Another French soldier died after his weapon went off as he was riding in an armoured vehicle near the Tagab district, in an area east of Kabul where French forces are deployed in the NATO mission in Afghanistan.