Canada's foreign ministry was hit by a cyberattack last week that is still preventing diplomats from accessing certain online services, federal cyber security agencies confirmed on Monday. 

A day after the attack, which took place on January 19, Canada's federal cyber security agency warned that critical infrastructure needed stronger defences against "Russian state-sponsored cyber threats".

However, Canada's government said on Monday that it did not know the origin of last week's attack.  

"There is no indication that any other government departments have been impacted," the Treasury Board of Canada, which manages government operations, said in a statement.

Noting that the Canadian government faces daily cyber threats, the department said these "can result from system or application vulnerabilities, or from deliberate, persistent, targeted attacks by outside actors to gain access to information."  

The revelation of the attack comes with international tensions rising around Ukraine, which the West believes is under threat of a Russian invasion. 

In recent days, Kyiv has claimed to have "evidence" of Moscow's involvement in a major cyberattack that targeted several Ukrainian government sites. 

The Kremlin has denied any Russian involvement.