British and French nuclear submarines HMS Vanguard and Le Triomphant collided in the Atlantic earlier this month, according to The Sun, a UK newspaper.
The newspaper reported Monday that the collision is believed to have occurred on February 3 or 4.
The two submarines came into contact at very low speed. Both submarines remained safe, Britain's most senior sailor, Jonathan Band said in a statement.
Both Britian and France insisted nuclear security had not been compromised.