A homicide bomber targeting a Canadian military convoy killed a child and wounded a NATO soldier and three other people Saturday in southern Afghanistan, officials said.

The bomber rammed his explosives-packed vehicle into a passing military convoy on the main highway linking the southern city of Kandahar with Herat in the west, said Ghulam Azrat, a regional police officer.

A child, who was at the side of the road as his family worked in nearby fields, was killed in the blast, Azrat said. Another child and a man, members of the same family, were injured, he said.

A NATO statement said a NATO soldier, who was not identified, was also wounded.

Meanwhile, a mortar attack in NATO's largest base in southern Afghanistan on Friday left three soldiers wounded, said Lt. Col. Angela Billings, a spokeswoman for NATO. The attack occurred in Kandahar Air Field, a vast military base and airport on the outskirts of city of Kandahar, she said.

There are some 36,000 troops serving in NATO's International Security Assistance Force.

Also Saturday, the United Nations mission in Afghanistan said that those holding a kidnapped Italian reporter and his two Afghan colleagues should show their humanity by freeing them.

Daniele Mastrogiacomo, 52, a reporter for Italian daily La Repubblica was kidnapped along with two Afghans traveling with him on March 5 in the Nad Ali district of southern Helmand province. Taliban insurgents have claimed responsibility.

"Mastrogiacomo is a well known journalist whose sympathies for the people of Afghanistan should be beyond doubt to anyone," the U.N. mission in Afghanistan said in a statement.

Mastrogiacomo appeared in a video shown on Italian television Wednesday, appealing to Italian Prime Minister Romano Prodi to work for his release. Prodi said that no efforts will be spared.

Foreign Minister Massimo D'Alema said Thursday that Italy was not negotiating with the Taliban, but added that humanitarian groups were in contact with them, "and the government is doing all it can with the necessary discretion."

Mastrogiacomo, a father of two, had been on assignment in Kandahar, the Taliban's former stronghold in southern Afghanistan, when his newspaper lost contact with him on March 4.