U.S. Secretary of State Hillary Clinton was hospitalized over the weekend in New York after her doctors discovered a blood clot during a routine medical examination, her spokesman, State Department Deputy Assistant Secretary Philippe Reines, said.

Clinton, who had taken a few days off to rest after sustaining a concussion after she fainted on Dec. 15, was hospitalized Sunday for treatement of a blood clot in an unspecified part of her body and is taking anti-coagulants.

Doctors expect to keep Clinton in the hospital for observation for 48 hours and "will continue to assess her condition, including other issues associated with her concussion," Reines said.

Clinton's doctors "will determine if any further action is required," Reines said.

The 65-year-old Clinton has kept up a blistering pace as the top U.S. diplomat, undertaking numerous foreign trips.

The secretary of state's fainting spell earlier this month was blamed on a stomach illness that caused her to become dehydrated and weak.

Clinton cancelled all her foreign trips and her appearance before Congress to discuss the attack on the U.S. Consulate in Benghazi, Libya, on Sept. 11 in the wake of her illness.

The former first lady and senator said she would not stay on as secretary of state in President Barack Obama's second term.

Clinton has also denied reports that she plans to run for president in 2016. EFE