WASHINGTON/NEW YORK, Dec 31: US Secretary of State Hillary Clinton has been hospitalised after doctors discovered a blood clot during a follow-up examination related to a concussion she suffered recently, the State Department said.

She was taken to New York Presbyterian Hospital on Sunday afternoon and is expected to remain there for two days as doctors monitor her condition.

She was receiving anticoagulants but “her doctors will also look at other issues associated with the concussion, Deputy Assistant Secretary of State Philippe Reines told reporters. “They will determine if any further action is required.”

The statement did not specify where the clot was discovered.

Secretary Clinton, 65, was suffering from a stomach virus earlier this month when she fainted because of dehydration, causing the concussion.

She spent the Christmas holidays with her family last week after working from home.

She was scheduled to return to work at the State Department this week. Her illness also prevented her from testifying before the House Foreign Affairs Committee on an attack on the US Consulate in Benghazi, which killed the US ambassador to Libya and three other Americans. Deputies Thomas Nides and Bill Burns appeared in her place.

Secretary Clinton is completing her tenure early this year after serving in the Obama administration for four years. She travelled nearly a million miles during her tenure, which media reports claim might have contributed to her illness.

She plans to step down from the post when Senator John Kerry — President Barack Obama's choice to replace her — is confirmed by the Senate.