A man in an Afghan police uniform has shot and killed an international service member, Nato said, raising the death toll to 10 in such attacks in the space of two weeks.
The surge in violence by Afghan allies against their international partners has raised doubts about the ability of the two forces to work together at a key transition time. Afghan forces are expected to take over security for the country by the end of 2014, when the majority of international combat forces are scheduled to leave.
On the other side, a coalition air strike killed dozens of Taliban militants, including one of their leaders, officials said.
Few details were immediately available about Sunday's killing of a coalition member in southern Afghanistan. Nato said only that they and Afghan authorities were investigating. Afghan officials could not be reached for comment.
The Taliban have been actively recruiting members of the Afghan security forces, saying in a statement last week that they considered these turncoat attacks a major part of their strategy against international forces.
Once an anomaly, these attacks have been climbing in recent months. There have been 30 such turncoat attacks so far this year, up from 11 in 2011.
The month-long Ramadan fasting period that ended Sunday has been particularly violent. The Eid al-Fitr holiday on Sunday continued the trend. Insurgents killed two pairs of brothers with links to the government as well as three Nato service members in three separate attacks.
In the first attack, a bomb hidden in a cemetery in the southern province of Helmand killed a police chief and his brother who were visiting a family grave for the holiday. Seven of the men's family members were wounded in the early-morning blast in the provincial capital of Lashkar Gah, said the Helmand deputy police chief, Ghulam Rabbani.
Later in the western Farah province, gunmen on a motorcycle opened fire on the car of an intelligence service official as he was driving home from a family visit, killing him and his brother, who worked for the customs service.
In central Afghanistan, three Nato service members were killed when a vehicle struck a roadside bomb, officials said. Bamiyan Governor Habiba Sarabi said the blast went off in Kohmard district while the troops were out on patrol.