A suicide bomber killed eight Americans at a U.S. base in eastern Afghanistan Wednesday, while another bomb killed four Canadian soldiers and a journalist in the south of the country.
U.S. officials say a bomber detonated his explosive vest inside the Forward Operating Base Chapman in Khost province. The military said no U.S. or NATO troops were killed or wounded in the blast, but few other details about the incident were released.
U.S. media reports quote unnamed officials who said the eight Americans killed were working for the CIA.
Khost borders Pakistan's North Waziristan tribal region, where Taliban militants and their allies launch cross-border attacks.
In a separate attack, the Canadian defense ministry says four Canadian soldiers and a Canadian journalist were killed Wednesday when their convoy hit a roadside bomb while on patrol just outside the southern city of Kandahar.
The journalist was identified as 34-year-old Calgary Herald reporter Michelle Lang. A Canadian civilian official was wounded in the blast.
The Canadian newspaper says Lang is the first Canadian journalist to die in the Afghan war since Canada joined the international mission in 2002.
In other news, a spokesman for international troops in Afghanistan says NATO so far has no direct evidence to back up Afghan government claims that foreign troops killed 10 civilians in eastern Afghanistan on Sunday.
Colonel Wayne Shanks told reporters Wednesday that NATO has requested an immediate joint investigation into the incident.
Afghan government investigators earlier concluded that foreign troops killed civilians - including school children - during Sunday's operation in the Narang district of Kunar province.
NATO released a statement Wednesday saying its forces were targeting insurgents when troops came under fire. The alliance says nine people were killed when NATO forces returned fire.
Hundreds of university students took to the streets in Kabul and in the eastern city of Jalalabad Wednesday to protest the killings.
Some information for this report was provided by AFP, AP and Reuters.