The incident came as Trump supporters demonstrated against counting of votes in battleground states after the incumbent president alleged voter fraud without providing evidence.
The four Congresswomen, who were elected first in 2018, have already been part of committees such as the financial industry, foreign affairs and the federal budget.
A man, wearing a 'BBQ, beer, freedom' tank top, barged into the news conference in Clark County in Nevada claiming that Joe Biden was "stealing the election."
Counting of votes in the key battleground states will go beyond Tuesday night and it won't be until at least a week till Americans will be their next president.
Political observers have been cautious about Joe Biden's win citing Thomas E Dewey's surprise defeat to Harry Truman in 1948. But, can Trump pull off a Truman-style win in 2020?