The incident occurred Saturday night in Sangin district in southern Helmand province, said military spokesman Capt. Drew Gibson.
"We can confirm with regret that two British soldiers were killed. Their base came under attack from small arms fire and RPGs (rocket propelled grenades)," he said.
Gibson said other soldiers were also wounded in the attack but declined to say how many.
The coalition issued a statement saying that along with the two soldiers killed, a coalition interpreter also died in the attack.
Four other coalition soldiers were wounded but a coalition spokesman refused to confirm their nationalities. They are listed in stable condition at a hospital, the statement said.
Last week, two other British soldiers were killed in an attack in the same district of Helmand province.
The deaths come amid a massive anti-Taliban campaign in southern Afghanistan involving more than 10,000 Afghan and coalition soldiers. It is the largest military offensive since the former regime's ouster in late 2001.
Britain currently has some 3,300 troops involved in the current military operation.
In a separate incident in the same district, 11 militants were killed by Afghan forces Saturday night during search operations, said Helmand provincial police chief Ghulan Nabi Malakhail. No Afghan soldiers or police were injured.
The police chief said Afghan forces came under fire from suspected militants and they fired back, killing the 11 fighters. All the enemy's bodies were found, he said.