Police mass at scene of Occupy protest in Washington WASHINGTON (Reuters) - Police officers wearing helmets and carrying shields arrived at the site where protesters with the "Occupy" movement have been staging a demonstration since October, but it was not immediately clear whether they would evict the protesters. The U.S. National Park Service had put the protesters on notice that it would start enforcing a ban against camping in McPherson Square, a park located just blocks from the White House. The police arrived at the park before dawn, wearing protective gear and setting up barricades. Protesters are targeting the growing income gap, corporate greed and what they see as unfair tax structure favoring the richest 1 percent of Americans. News footage from the site showed police speaking with the "Occupy DC" protesters in the park and removing a large tarp decorated with stars and moons over a statue of U.S. Civil War General James McPherson at the center of the square. The number of protesters in the Occupy DC camps fluctuates, but city officials estimate there are fewer than 100. The demonstrators had set up tents and were sleeping in the park. Despite their small numbers, the Washington protesters have received outsized media attention because their camps are just blocks from President Barack Obama's official residence. The National Park Service regulates both parks and forbids camping on federal land not designated as a campground. Local city officials have complained about squalor, rats and trash. Writing by Will Dunham; Editing by Vicki Allen