Six foreign soldiers were killed in the conflict-ridden Afghanistan on a single day Monday, according to press releases issued by the NATO-led International Security Assistance Force (ISAF).

Three American soldiers were killed Monday afternoon in an engagement with enemy forces in the restive southern region of Afghanistan, ISAF said in a statement.

In another firing incident in eastern Afghanistan, one ISAF service member was killed and another died of his wounds.

The six deaths of foreign troops on Monday came after an ISAF service member was killed in an IED strike in southern Afghanistan, making Monday a deadly day for foreign soldiers.

Monday's casualty brings the number of NATO service members fatalities to eight since Saturday. ISAF press releases issued earlier said two ISAF soldiers were killed in two separate IED attacks in southern Afghanistan in the weekend.

NATO-led forces casualties had been registered 512 in 2009, according to media reports. Militancy and conflicts is predicted to increase this year as both Taliban-linked insurgents and the NATO-led forces have speed up activities to consolidate their grips.