U.S. President Donald Trump is facing growing pressure in the last days of his presidency after his supporters breached the barricades and stormed into the U.S. Capitol building as Congress met inside to certify Joe Biden's presidential election victory in Washington, D.C. on January 6.

What we know so far:

• The center of Washington was put on lockdown due to growing security concerns ahead of the presidential inauguration, and security is particularly tight around the White House and Capitol Hill.

• The FBI has warned of possible armed protests in all 50 U.S. states and Washington, D.C., in the days before Biden is inaugurated as the new U.S. president.

• Donald Trump has become the first U.S. president to be impeached twice, a week after violent protesters stormed the U.S. Capitol. 

• Trump urged Americans to be "united" and avoid violence in his first comments after being impeached Wednesday.