Demonstrators streamed into downtown Washington on Saturday for what officials said could be the biggest collection of day-long local protests so far over police brutality and racial oppression in the United States. On a hot and humid day, people carrying protest signs marched, many with their children, toward the area around the besieged White House, where authorities used tan military Humvees and dump trucks to cordon off large sections to vehicle traffic.

Here are some significant developments:

• It was the ninth day of massive protests in the District over the death of George Floyd by a Minneapolis police officer, and the Trump administration’s militant approach to the unrest that has gripped cities across the country. Numerous rallies were unfolding across the District throughout the day, from the Lincoln Memorial, to Freedom Plaza, to Capitol Hill.

• Lafayette Square, where a heavy security fence blocked any approach to the White House, a block away, was again a focal point Saturday. The scene of violent confrontations between police and protesters several days ago, it was calm, and the fence was hung with protest signs, an American flag, and a torn yellow strip of police tape that read: “Crime Scene.”

• Mayor Muriel E. Bowser greeted thousands of protesters gathered on the street she renamed “Black Lives Matter Plaza” a day earlier. She called out the federal police’s actions Monday in front of “the people’s house,” saying that today she “pushed the Army away from our city.”

• The D.C. National Guard confirmed it is investigating whether the use of one of its helicopters, used Monday in support of law enforcement on the ground near Lafayette Square, was appropriate. The helicopter’s use occurred the same night that police and federal agents aggressively rushed off a crowd to clear a path for President Trump to walk from the White House to St. John’s Episcopal Church.