Cairo (CNN) -- Interim Egyptian Prime Minister Essam Sharaf was being treated for exhaustion at a Cairo hospital late Monday but had not suffered a stroke, as reported earlier, his spokesman said.
The spokesman, Ahmed Saman, said doctors were performing brain and cardiac tests on Sharaf late Monday at Cairo's Dar Al Fouad Hospital. No details of his condition were immediately available.
Earlier, Saman had said Sharaf was taken to the hospital after suffering a stroke. But the premier's office later described his ailment as exhaustion and fatigue after "a long day at work."
Sharaf, an engineer by training, was named prime minister in March. He leads a caretaker government under the military council that took power in February, when former President Hosni Mubarak resigned in the face of a popular revolt.
News of Sharaf's illness came the same day as a much-anticipated reshuffle of the Cabinet, with replacements announced for 14 of 27 ministers. The shakeup was an attempt to satisfy critics who say the current administration was not serious about the political and economic reforms demanded by protesters.
The new appointees were expected to be sworn in Monday afternoon by Field Marshal Mohamed Hussein Tantawi, head of the military council. But Saman said that ceremony was put off when one of the nominees -- Abdelfattah al-Banna, Sharaf's pick to lead the Antiquities Ministry -- turned down to job due to complaints about his appointment.
Al-Banna was to replace Zahi Hawass, one of the most well-known Egyptians internationally. He was removed after reports surfaced accusing him of questionable business deals and giving national treasures as gifts to the Mubaraks.
The new slate of ministers included new faces in several key posts, including the foreign and finance ministries. A reformer, Hazem Beblawi, was named finance minister and deputy prime minister as part of the shakeup.
But two key portfolios -- interior and justice -- did not change hands. Experts say this may spark further protests in the coming days, despite the recent firings of more than 600 top police officials last week by the Interior Ministry.
Journalist Mohamed Fadel Fahmy contributed to this report.