(CNN) At least 42 people, mostly soldiers and one child, were killed when attackers launched four suicide car bombings at security targets in a major Yemeni city, two senior government officials told CNN.
The attacks occurred in Mukalla, a southeastern port city in Hadramaut province.
At least 30 people were injured -- all security officers except for five civilians, according to the two officials, both of whom are in the provincial governor's office.
One of the attacks targeted a military compound near a government intelligence building. The others targeted military checkpoints. A child walking near one of the checkpoints was killed.
Amaq, a media voice of ISIS, said in a statement published on Twitter that four ISIS attackers targeted a joint security base.
The areas attacked had been mostly controlled by al Qaeda in the Arabian Peninsula andd ISIS before government forces started a campaign against that group. AQAP and ISIS been responsible for least 40 attacks over the last three months alone in Hadramaut, the Defense Ministry said.
Last month, at least 30 troops were killed and dozens others injured when when an AQAP suicide bomber attacked a military base in Mukalla. The suicide bomber approached the main gate for the military base and detonated a bomb when recruits crowded the gate.
Yemen has become a proxy battleground for Saudi Arabia and Iran. Yemen's minority Houthis, who are Shiite, rebelled last year against the Sunni-led government of President Abdu Rabu Mansour Hadi, which is backed by Saudi Arabia.
A Saudi-led coalition got involved in march 2015 by launching airstrikes in support of Hadi against rebel targets in Yemen. Thousands of civilians have been killed in the violence. Government forces and the Saudi-led coalition also have fought against AQAP and ISIS, both of which are anti-government Sunni terror groups.