The forces are stationed outside the capital to defend the city against thousands of protesters who are on their way to Tripoli to liberate the city.
Reports say the military forces are worn out as they have been on alert for the past few days.
Over one thousand people have been killed and more deaths are feared as Gaddafi's crackdown on protesters continues.
Meanwhile, the humanitarian group Doctors Without Borders has voiced deep concern over the critical condition of the wounded in Libya, including the city of Benghazi.
"All information we receive points towards a critical situation in terms of medical care for the injured," Arjan Hehenkamp, the group's director of operations, said in a statement on Friday.
“It is unacceptable that medical staff and supplies are kept away from people who need them,” he went on to say.
According to the official, a team carrying medical supplies has been blocked at the Tunisian border. Another team which had reached Tripoli by airplane was also denied entry to the country and had to turn back.
Hehenkamp said that due to insecurity, travelling by road to the capital was almost impossible but added that a six-member team of the group with a truckload of medical supplies has arrived in Benghazi.
This comes as UN Secretary General Ban Ki-moon has called on the Security Council and the international community to take concrete action against the Libyan regime.
Ban Ki-moon urged the Security Council to act quickly on a proposed package of UN sanctions to force Gaddafi to end its violent crackdown on people.
"It is time for the Security Council to consider concrete action," he told the council.
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