PHILADELPHIA — An already acerbic Pennsylvania Senate race got even more combative this week after Lt. Gov. John Fetterman said he won’t attend a debate that he and Republican opponent Mehmet Oz were invited to next week.

The debate, at the KDKA TV station in Pittsburgh, was scheduled for next Tuesday. Fetterman’s campaign officially declined the invitation this past Tuesday, unleashing a deluge of insults from Oz’s campaign, which has challenged him to five debates.

Oz — who has trailed Fetterman by between 5 and 10 percentage points in most public polls and was hugely outspent on TV advertising over the summer — is eager to get his message out on live TV against Fetterman. Given his long history as a TV doctor, his campaign would expect him to perform well on a debate stage.

Fetterman, who was also criticized in the Democratic primary for avoiding debates, is not a strong debater, and is also still recovering from a stroke that sidelined him from the campaign trail for months.