Troops loyal to a Libyan general tried to block internationally recognised Prime Minister Abdullah al-Thinni from visiting the eastern city of Benghazi at the weekend as he looked to show support for his soldiers battling Islamist groups.
Army members under the control of General Khalifa Haftar tried to deny Thinni's plane permission to land on Sunday and later briefly halted his convoy during the visit, a minister and military officials said.
"When Thinni's plane was approaching Benghazi an officer came and said permission to land had been denied," Interior Minister Omar al-Zanki said. Thinni still managed to land and hold a cabinet meeting in Benghazi after visiting military commanders, he added.
The incident may signal a possible rift in the military alliance between the Thinni's government and Haftar just months after launching an offensive against Islamist fighters in Benghazi - part of turmoil gripping the oil producer four years after the downfall of Muammar Gaddafi.
Last year, Thinni and his allied parliament formed an alliance with Haftar after his government was forced out of Tripoli following the seizure of the capital by an armed group called Libya Dawn in August.
Thinni's regular army, largely destroyed during the NATO-backed revolt in 2011, has been to weak to fight Islamists roaming around eastern cities like Benghazi.
While the alliance has managed to win back territory in Benghazi, Haftar has drawn criticism for flying air strikes on civilian airports and seaports in an attempt to regain Tripoli.
A senior officer travelling with Thinni confirmed that the convoy of vehicles carrying the officials was stopped by an armed group of 70 soldiers when it tried to leave Marj, a city near Benghazi and home to Haftar's main base.
Haftar's spokesman Mohamed El Hejazi did not confirm the details but accused Thinni of having visited Benghazi without permission.
"We are unhappy with Thinni's visit to Benghazi because he didn't ask for a permission from the army commander and chief of staff," he said. "His meeting with the commanders of the frontline was not his business as he doesn't even hold a military command to meet them."
Hejazi added that only the president of the House of Representatives would have been allowed to inspect troops as the top commander.
Thinni has been challenged by a rival government set up in Tripoli after Libya Dawn seized the capital. The Tripoli rulers have not been recognised by world powers but control ministries.