Protesters with the Occupy Wall Street movement camped in the US capitol vowed they would \"re-occupy\" a park a few blocks from the White House after the city mayor called for their removal. Washington Mayor Vincent Gray asked the National Park Service earlier Thursday to remove protesters from McPherson Square, one of two downtown sites being used for an encampment by \"Occupy Washington\" and \"Occupy DC\" demonstrators. Gray said in a letter to National Park Service director Jonathan Jarvis that he wants the protesters removed to eliminate rats and trash and allow restoration of the park. He suggested the protesters in McPherson Square could be moved to the other encampment in nearby Freedom Plaza. The protesters at both sites have been there since October to demonstrate their outrage about economic inequalities. Some, however, pledged defiance if forced to move by authorities. \"The rats were here before we ever got here,\" said Tracy Keith, a biological researcher from Chapel Hill, North Carolina, who has camped in McPherson Square since October 4. \"This is just a lame excuse. It\'s just inconvenient to have protesters here in DC,\" she told AFP. If police do close down the camp, \"we will re-occupy,\" Keith added. Robert Dilley, a commercial truck driver from Vernon, New Jersey, also camped in McPherson Square, said, \"We can go to any other park and essentially do the same thing.\" He told AFP the protest and encampment are important \"to get our voices heard. This is a movement in its infancy.\" Dilley also said he doubted efforts to remove the protesters would succeed after they won a court judgment endorsing their right to maintain a vigil on federal land. The court judgment means \"we have every right to do what we\'re doing,\" he said. Gray\'s letter to the National Park Service said a DC Department of Health report showed concern is growing about the threat to public health and safety. \"The most serious of these concerns include dangerous rat infestation as well as the serious potential for communicable disease, hypothermia and food borne illness,\" Gray wrote. Both encampments are on property controlled by the National Park Service. Other concerns mentioned by Gray include fire threats from candles and propane heaters, inadequate human waste removal and food sanitation. The city\'s Health Department director Mohammed Akhter reported the health problems are more severe at McPherson Square than Freedom Plaza, where sanitary procedures are being followed more carefully.