Hours before a Wednesday deadline, the Trump campaign said it wanted a recount in the counties of Milwaukee and Dane, alleging irregularities.
Mr Trump has been making unsubstantiated claims of fraud and refused to authorise a handover.
Mr Biden says delaying the transition will damage the US pandemic response.
The Trump campaign has filed a flurry of lawsuits contesting the results in key states, although election officials say there is no evidence of widespread irregularities.