Boko Haram's leader said in a video obtained by AFP on Thursday that the group was behind a daring raid on military installations in the north Nigerian city of Maiduguri earlier this month, AFP reports.
"Allah the Almighty has given us victory in the attack we launched inside Maiduguri (which was) called Borno in ancient times," said Abubakar Shekau in a 40-minute clip.
Speaking in Arabic, Hausa and Kanuri widely spoken in northeast Nigeria, Shekau added: "We stormed the city and fought them (and) Allah blessed us with lots of booty."
The video, which was obtained through an intermediary, shows Shekau dressed in military fatigues with a turban and Kalashnikov assault rifle leaning on his chest.
He speaks for 19 minutes in all while the rest of the tape shows images of burning buildings and aircraft said to be from the December 2 attack in Maiduguri, which is capital of Borno state.
It also shows a display of weapons the banned Islamist group says it seized in the attack, including dozens of Kalashnikovs and rockets.
The authenticity of the tape could not be verified independently.
Gunmen who arrived on pick-up trucks besieged an army and air force base, destroying aircraft, razing buildings and setting shops and petrol stations ablaze, witnesses said.
The early morning raid was seen as significant because the Nigerian military had previously claimed to have pushed the militants out of urban centres and into more remote, rural areas.
Local people reported that the attackers were carrying AK-47 assault rifles and rocket propelled grenades in the assault, which prompted the local authorities to impose a city-wide curfew.
Maiduguri is considered the spiritual home of Boko Haram, whose name roughly translates from Hausa as "Western education is sin".
The group's aim is to impose a harsh form of Islamic law or sharia across the country.
Thousands of people have died in deadly violence since 2009, both at the hands of the militants and as a result of the military response to the violence.
In the Maiduguri raid, Nigeria's military said 24 militants were killed and two service personnel were wounded.
But Shekau said only seven fighters lost their lives -- three in suicide bombings, three were shot and one in "friendly fire".
At least two local residents were also killed, people in the city said.
The US State Department in July offered a reward of up to $7 million for information leading to the arrest of Shekau.
In the video, he said "the whole world" feared him, name-checking US President Barack Obama, French President Francois Hollande, Israeli Prime Minister Benjamin Netanyahu and even the late British premier Margaret Thatcher.
Shekau singled out in particular the United States, which on November 13 designated Boko Haram and its offshoot Ansaru as international terror groups.
"You are boasting you are going to join forces with Nigeria to crush us. Bloody liars," he said, in an apparent reference to a pledge by Washington to support Abuja in the fight against the extremists.
"You couldn't crush us when we were carrying sticks," he said, adding: "By Allah, we will never stop. Don't think we will stop in Maiduguri.
"Tomorrow you will see us in America itself. Our operation is not confined to Nigeria. It is for the whole world."
Shekau's claims about the international nature of Boko Haram stand at odds with analysts' general assessments that the group is largely Nigeria-based.
But the United States has said the group and Ansaru have links the wider Islamist jihadi network, in particular Al-Qaeda in the Islamic Maghreb (AQIM), which has provided limited training and funding.