Aftershocks are rattling central Oklahoma days after a record-setting earthquake hit the state, which is seeing a dramatic, unexplained increase in seismic activity.

The U.S. Geological Survey recorded at least five tremors Monday, the strongest being a 4.7 magnitude quake near Prague, about 50 miles east of Oklahoma City.

The federal agency received reports of it being felt in Kansas City, Mo., and Little Rock, Ark. There were no immediate reports of damage or injuries.

But damage reports from Saturday's record-setting 5.6 magnitude quake are still coming in, ranging from cracks in the walls of homes to a county bridge. The quake was felt in parts of six other states.

Oklahoma had about 50 earthquakes annually until 2009. Then the number spiked, and 1,047 quakes shook the state last year.