GARISSA (Reuters) - A remote-controlled bomb hit a police vehicle in Kenya's Dadaab refugee camp near the border with Somalia on Tuesday, a senior local official said, the second such incident in the camp in less than two weeks. Kenya has been plagued by a wave of attacks since it sent hundreds of soldiers into neighboring Somalia last month to rout al Qaeda-linked Islamist militants it blames for a spate of kidnappings and cross-border raids. "There was an explosion in Hagadera that struck a police car," Dadaab District Commissioner Ndambuki Muthike told Reuters, referring to one of Dadaab's three camps. "We heard that the car has been completely destroyed." A doctor working in a clinic several kilometers (miles) from the blast site said he heard a loud explosion. "We immediately received a call from the police who told us to prepare a space for four people who had been injured in the blast. We were told two of them were in a critical condition," said the medic who declined to be named. A Kenyan police jeep escorting U.N. vehicles struck a land mine in the same area earlier this month, highlighting the mounting threats facing aid workers and refugees in the world's largest camp. It was not immediately clear if the police vehicle in Tuesday's attack was part of a convoy.