(CNN) -- Gunmen on Friday shot dead a Nigerian Islamic traditional leader in the northeastern state of Borno as he and other Muslim royals were heading to a funeral, the state government said.
Idrissa Timta, emir of the town of Gwoza, was killed as he and two other emirs were traveling to the funeral of an emir in neighboring Gombe state, Borno government representative Bab Ahmed Jidda said.
Jidda said the attackers are suspected to be members of the Islamist militant group Boko Haram. The country's defense ministry, which also reported the attack, called the gunmen a "band of terrorists" but did not identify their affiliation.
The emir of Uba, Ali Ibn Ismaila Mamza, and the emir of Askira, Abdullahi Ibn Muhammadu Askirama, escaped unhurt, according to Jidda.
The gunmen specifically targeted the vehicle holding the three emirs and opened fire, Jidda said.
A police escort was shot and injured in the attack, Jidda said.
Wali Ibrahim, a member of the Gwoza royalty and a close aide to the slain emir, said the gunmen opened fire from hilltops overlooking the highway.
"We came under heavy gunfire from the hills, which forced the convoy to break up in disarray," said Ibrahim, who was in Timta's entourage.
"We returned to a military checkpoint not far from the scene of the attack and reported the incident to soldiers there, but to our surprise they made no effort to go after the attackers," Ibrahim said.
"By the time we returned to the scene, we met the emir dead inside the vehicle with gunshots," he said.
Troops were dispatched to the area after the attack and are trying to find the assailants, the defense ministry said.
Boko Haram has repeatedly targeted Nigeria's Islamic emirs, accusing them of selling out by submitting to the authority of the secular government.
The emirs are from traditional royal families and often serve as liaisons between their communities and the secular government. Timta's late father had been a chief in Gwoza.
In July 2012, Nigeria's third-most powerful emir, the shehu of Borno, Umar Garbai El-Kanemi, survived a suicide bombing as he left a mosque near his palace.
The traditional leader survived the attack, but five other people were killed.
In August 2012, a suicide bomber tried to kill the emir of Fika in northeastern Yobe state as he left Friday prayers near his palace in the town of Potiskum.
That emir survived the blast, though his police guard was killed.
Last year, Nigeria's No. 2 Islamic leader, Abo Bayero, the emir of Kano, survived an attack on his convoy. Five people, including three of his bodyguards, died.
There have been calls from activists for Nigeria's emirs to play a greater role in curbing Boko Haram, which has waged a campaign of violence -- especially in northeastern Nigeria -- with the aim of imposing a stricter enforcement of Sharia law across Nigeria.
Boko Haram, which means "western education is a sin," still is holding more than 200 girls it abducted last month from a school in Chibok, also in Borno state.
CNN's Nana Karikari-apau and Jason Hanna contributed to this report.