One American and one Canadian soldier were killed when suspected Taliban insurgents attacked a U.S.-led coalition military base in Southern Afghanistan Wednesday.

Twelve or more of the attackers were killed in a counter-attack.

The attack occurred Wednesday morning in Afghanistan's Helmand Province, which is increasingly being considered a Taliban stronghold.

U.S. officials have confirmed the coalition causalities, and say the coalition counter-attack defeated a significant enemy force.

"Coalition forces employed a variety of combined arms, including close air support, and are believed to have killed at least a dozen insurgents," said Lieutenant Mike Cody, a coalition spokesman based in Kabul.

He says several wounded coalition soldiers were flown to a military hospital in the southern city of Khandahar.

Local media report Taliban officials are claiming responsibility for the attack.

Coalition forces have been on guard for an expected spring offensive by Taliban insurgents.

Fighting typically intensifies this time of year when mountain snow begins to melt and the countryside becomes more accessible.

In a separate incident, a suicide bomb blast, also in Helmand, killed at least six Afghan soldiers late Tuesday.

And two local police officers were killed during an attack in neighboring Kandahar by suspected Taliban militants.

Officials there say insurgents tried, but failed, to occupy a police checkpoint.