CAIRO, Dec 26 (Aswat Masriya) - The body of abducted teenage daughter of killed Egyptian doctor and wife in Libya has been found late Thursday, a medical source at Ibn Sina Hospital in Libya's central coastal city of Sirte said.

The girl's body was found west of Sirte, the source added, without revealing further details.

The body has arrived at the hospital Thursday evening, state-run MENA quoted the medical source as saying.

Unidentified assailants killed a Coptic Egyptian doctor and his wife in Sirte and kidnapped their daughter on Tuesday.

Egypt's foreign ministry demanded swift investigation by Libyan authorities into the incident, and bringing the perpetrators to justice.

The ministry said in a statement that it is following up with news of the Egyptian nationals' death, adding that there is coordination with the designated Libyan authorities concerning the incident.

It reiterated its warning to all Egyptians residing in Libya, calling on them to avoid any conflict areas. It renewed its travel alert to the neighbouring country, urging those travelling to Libya to secure a visa from the Libyan embassy prior to their travel.

Militant fighting in Libya has recently intensified in measures unprecedented since the overthrow of late Libyan President Muammar Gaddafi in 2011. Army general Khalifa Haftar declared war on Islamist forces within Libya since May.

Two Egyptians were killed in western Libya on December 14, and four others were injured in clashes between the Libyan army and Islamist militants near the Libyan border with Tunisia.

Several Egyptians had been killed and kidnapped during the unrest in Libya. Most of the Egyptian nationals working there have been evacuated from the conflict-torn country.