A US base and an Italian military convoy were targeted in separate attacks in Somalia on Monday.
Al-Shabaab militants staged a simultaneous car bomb and gun attack on the Baledogle US facility, while the Italian vehicles were hit by an explosion in the country's capital of Mogadishu, according to officials.
The US base is located in the south of the East African nation, about 100 kilometers (62 miles) northwest of Mogadishu. American forces use the base to train Somali commando units.
Abdifitah Haji Abdulle, deputy governor of the Lower Shabelle region, said fighters detonated explosives at the entrance of the base before attempting to storm the premises. He added that fighting took place outside the camp, which houses US and Somali soldiers. There was no immediate report of casualties.
Somali National Army Radio reported that Somali forces and their US partners had "repelled" the coordinated terrorist assault.
Separately, the Italian Defense Ministry said two of its light armored vehicles were hit by a blast in the capital on Monday morning, after returning from training with Somali security forces. "At the moment, there are no consequences for the Italian personnel," the ministry said.
Reuters also reported seeing a seriously damaged armored vehicle displaying a small Italian flag sticker.
Al-Shabaab militants claimed responsibility for the attack on the US base, according to the group's affiliated website, Somalia Memo. The militants justified the assault by saying the facility was often used to launch drone attacks against Al-Shabaab in the region.
US Africa Command is investigating the attack, it said in a statement.
"We are working to confirm details on the incident and will have more information as soon as we can confirm facts on the ground," it said.
The attack comes as Al-Shabaab faces increasing pressure in the region after losing control of several key areas including Bariire, where US Navy SEAL Kyle Milliken was killed in May 2017.
At the same time, Somali, African Union and US troops have recently stepped up operations against the group.