The incident occurred while Mr Trump was on the golf course at Trump International Golf Club in West Palm Beach.
The incident in Butler, Pennsylvania., occurred on Saturday evening.
“We have made this decision to block these two websites (Facebook and Twitter) from being accessed from our network,” it added.
Mr. Trump’s concession comes moments after the country’s parliament affirmed Biden’s Electoral College victory.
William Barr’s position undermines his principal’s claims of widespread voter fraud in last month’s election.
The legal adviser of Mr. Trump’s campaign insisted that the state recounted illegal ballots.
There have only been two statewide recounts in U.S. presidential elections over the last 20 years.
The U.S. president has yet to publicly concede this month’s presidential election to Joe Biden.
Mr. Biden’s victory was projected on Saturday.
“The simple fact is this election is far from over,” Mr. Trump said in a campaign statement.
