Retired Libyan Gen. Khalifa Haftar

Rogue former Gen. Khalifa Haftar of Libya, shown at a news conference last month, reportedly survived an assassination attempt Wednesday. (AFP/Getty Images / May 17, 2014)

A rogue former army general in Libya survived an assassination attempt Wednesday as fighting and tension continued to escalate between his forces and Islamist militias loyal to the ruling General National Congress.

The Libyan state news agency, LANA, quoted the head of former Gen. Khalifa Haftar's air division as saying that five soldiers were killed when a vehicle exploded inside a farmhouse that is used as a headquarters for Haftar's meetings just outside the eastern Libyan city of Benghazi.

The air division chief, Gen. Sagr Al Jerushi, was slightly injured in the assault, according to LANA. He vowed to retaliate against what he called a terrorist attack. Haftar's spokesman, Mohamed Hejazi, accused Islamist militias of plotting and executing the attack.

"We hold the terrorists responsible for this attack. This sort of suicide bombing is, of course, the work of terrorists and extremists," Hejazi told reporters.

The attack came on the same day that the International Committee of the Red Cross, or ICRC, said one of its staff members was killed by armed men in the Libyan city of Sirte, the hometown of the late Libyan strongman Moammar Kadafi.

Michael Greub, a 42-year-old Swiss national, was head of the organization's sub-delegation in Misrata, Libya, the organization said.

"The ICRC vigorously condemns this heinous attack," Yves Daccord, the ICRC's director-general, said in a statement. "Michael was just leaving a meeting with two colleagues when their vehicle was targeted by a group of armed men." The two colleagues were not hurt.

Daccord said the organization was "devastated and outraged."

Haftar was prominent in the 2011 revolt against Kadafi. Last month he launched an offensive he called "Operation Dignity" against bases belonging to armed Islamist groups in Benghazi.

The fighting escalated Monday, when at least 15 people were killed and 42 injured in a battle in Benghazi between Haftar's forces and those of Islamist militias, according to LANA.

Acting Prime Minister Abdullah Thani and the regular army’s chief of staff have characterized Haftar’s unauthorized attacks as tantamount to a coup. Some military units have reportedly defected to his force, which he calls the National Army.

After escalating his raids against a number of Islamist militias in Benghazi, Haftar was threatened by both the Ansar Al Sharia group and Al Qaeda in the Islamic Maghreb, which called him "an enemy of Islam."

The United States considers both of those groups to be terrorist organizations.

The Islamist-dominated ruling General National Congress branded Haftar an outlaw after he demanded that it be dissolved in favor of a military council that would lead Libya until parliamentary elections are held.

Instead, the legislative body pursued its efforts to appoint a new cabinet following the election of Ahmed Matiq as a replacement for interim premier Abdullah Al Thinni in a heavily disputed parliamentary session last month.

The General National Congress says steps are underway to form a new government. Al Thinni told LANA that the new government can't be formed until a decision is made on his legal appeal of Matiq's election.

The legislature, elected in 2011, has been criticized by various Libyan sects for endorsing Islamist militias, as well as failing to impose its central authority over armed tribes and militias across the North African nation.