Libyan officials say car bombings in eastern Libyan areas under control of the internationally-recognized government have killed at least four people and wounded about 20 others.
The officials say one of the attacks took place in the city of Tobruk, base of the contested Libyan parliament elected earlier this year.
Another explosion hit an air base in the city of Bayda, which is home to the Libyan government.
There has been no immediate claim of responsibility. Officials said three of the dead were soldiers.
The Associated Press is reporting that the Libyan military responded to the bombings by carrying out airstrikes on the city of Darna, an Islamist stronghold.
Many young people in Darna recently pledged allegiance to Abu Bakr al-Baghdadi, leader of Islamic state militants fighting in Syria and Iraq.
Both the government and parliament took refuge in remote areas in eastern Libya when Islamist-backed militias seized the capital, Tripoli, in August. Militants have also controlled most of Benghazi, Libya's restive eastern city, in recent months.
The Libyan government has struggled to establish its authority across the country, while militants have a large part of it under their control.
Last week, Libya's Supreme Court ruled that the country's internationally-recognized parliament is invalid, adding to an already tumultuous political scene in the deeply fractured North African state.
Some information for this report comes from AP, AFP and Reuters.