Hackers have stolen $2.3 million from the Wisconsin Republican party bank account used to support President Donald Trump’s re-election campaign in the key swing state, the party said on Thursday. Wisconsin Republican party Chairman Andrew Hitt told the Associated Press that the party noticed suspicious activity on October 22 and notified the FBI the next day. Mr Hitt said the FBI has launched an investigation. He noted that the attack apparently began as a phishing attempt and that the hackers altered invoices from vendors to funnel the money. The FBI did not immediately confirm the status of the investigation. The money in the account used to make quick spending decisions based on the state of the race. Polls show Mr Trump trailing former Vice President Joe Biden in the battleground state, and voters have already started to cast their ballots. "In keeping with our standard practice, the FBI neither confirms nor denies the existence of any investigation," said Tina Jagerson from the FBI's public affairs bureau. "We do not have any further comment."