The house of a Republican Senator's neighbor has been spray-painted with graffiti calling the GOP 'Nazis', 'rapists' and 'cross-worshipers'.

Police are investigating the graffiti scrawled next to the home of Pennsylvania Senator Pat Toomey.

One of the three messages, which were left late Saturday or early Sunday read: 'Nazi, Slavers, Rapists, Cross-Worshippers (sic) == GOP.'

It is believed 'cross-worshipers' is a reference to the GOP's heavy links to Catholicism.

Republican Senator Pat Toomey's neighbors' home in Pennsylvania has been vandalized with anti-GOP graffiti

The messages were spray-painted on Toomey's neighbors' home either late on Saturday night or early Sunday morning

One of the messages spray-painted on the home in Upper Milford Township, near Philadelphia, read: 'Look Out Toomey and Your Neo Nazi Republicans'

The second reads, 'Look Out Toomey and Your Neo Nazi Republicans,' and a third says '#AmericansAgainsttheRepublicanParty.'

Toomey says he's 'sickened by this disgusting, politically inspired hatred.'

The Republican's Democratic opponent also condemned the shocking vandalism.

Katie McGinty issued a statement calling the vandalism 'unacceptable' and said she hopes police 'hold the people accountable for it responsible'.

Toomey was asked about the graffiti after Monday night's televised debate with McGinty, and said he was 'extremely distressed and disappointed that our neighbors and friends would be subjected to something like that.'

Toomey lives in Upper Milford Township, near Philadelphia.

Toomey (pictured during a debate on Monday) said he was 'extremely distressed and disappointed that our neighbors and friends would be subjected to something like that'