Labour has been hit by a second cyberattack in 24 hours after hackers targeted the party’s digital platforms.

The party confirmed it had suffered a “sophisticated and large-scale” attack on Monday, with a second hit following on Tuesday afternoon.

Sources told Reuters it was unclear if it was the same hackers as on Monday or a copycat attack but there was currently nothing to link either incident to a foreign state.

A Labour spokesperson said: “We have ongoing security processes in place to protect our platforms, so users may be experiencing some differences. We are dealing with this quickly and efficiently.”

Both incidents are understood to be “distributed denial-of-service” (DDoS) attacks, where a network of computers is used to flood the target with requests, overwhelming its server and slowing it down or causing it to crash.

Labour said the attack failed due to the party’s “robust” security systems and it was confident that no data breach had occurred.

Reuters reported a third attack on the website of the Conservative Party had also taken place on Tuesday afternoon, citing two sources with knowledge of the matter.

The sources told the press agency there was currently nothing to link the attacks on either party to a foreign state.

One said the attack on the Tories was larger and appeared to be conducted by different hackers, but did not take down any party websites.

A Conservative Party spokeswoman had no immediate comment and said she was unaware of the attack.

The National Cyber Security Centre (NCSC), which is investigating the first attack on Labour, said it was relatively “low level” with no evidence of “state-sponsored activity”.

And a security official told The Independent: “This is seen as a low-level denial of service attempt with no evidence of it being carried out by a state actor.”

Jeremy Corbyn described the first incident as “very serious” and admitted the timing of the attack made him “nervous”.

Speaking at a campaign event in Blackpool, the Labour leader said: ”We have a system in place in our office to protect us against these cyberattacks, but it was a very serious attack against us,” he said.

“So far as we’re aware, none of our information was downloaded and the attack was actually repulsed because we have an effective in-house developed system by people within our party.