Four service members from the NATO-led force in Afghanistan were killed in two separate attacks on Sunday, the coalition said, the day after 30 US troops were confirmed killed in a helicopter crash that marked the deadliest single incident for foreign troops in 10 years of war. The NATO-led International Security Assistance Force (ISAF) said in a statement two were killed in an attack by insurgents in Afghanistan’s volatile east on Sunday. Another two were killed by insurgents in the south, it said, but gave no other details.