The bomber also wounded seven others and caused extensive damage to the hospital, which was being used to treat Libyan soldiers fighting "Islamic State" (IS), a security source said Sunday.

Two attempted suicide bombings also targeted Libyan forces near the center of Sirte but failed to cause casualties, the source added.

IS militants took control of the Mediterranean port last year, exploiting Libya's political turmoil and lawlessness to gain a foothold in the country. Militias allied with the UN-backed unity government launched an offensive a month ago to recapture the city. The brigades entered Sirte this week, and have repeatedly been targeted by suicide bombings, snipers and mines during the push to drive the militants out of the town.

Brig. Gen. Mohammed al-Ghasri said Sunday's attacks "infiltrated our siege" on the insurgents' main stronghold and targeted supply lines and medical units.

"They aimed to shake our ranks, to force us to retreat, but we remain steadfast," al-Ghasri said. "We are determined to finish the job before the end of the holy month of Ramadan."

Medical shortfalls

The progress of Libyan brigades in Sirte has been faster than anticipated. But officials in Misrata, where most of the troops come from, said their efforts against the militants were being hampered by a lack of medical supplies and capacity to treat injured fighters. Medical and security sources said at least 120 brigade members have been killed and more than 500 wounded in the siege.

"We appeal to the international community and international organizations to help us in providing necessary medical treatment for the wounded," Misrata medical official Aziz Issa said.

The loss of Sirte would be a major blow for IS. It is the only city held by the militants outside Iraq and Syria, where the group controls vast swaths of territory and several cities and towns.

nm/ rc(Reuters, AP, AFP)