Dozens of U.S. Park Police officers have converged on one of the nation's last remaining Occupy sites and are inspecting tents there.
The officers arrived before dawn Saturday at McPherson Square, just blocks from the White House, on horseback and in riot gear.
There were no clashes between police and protesters, though a Park Police spokesman says four people were arrested for disobeying a lawful order.
Police say they want to make sure protesters are complying with National Park Service regulations that allow demonstrations at the site but prohibit camping. Police are inspecting tents, and some officials are wearing yellow biohazard suits to avoid exposure to any communicable diseases.
Some demonstrators say the police are effectively evicting them by forcing them to remove any bedding material from their tents.