At "Ground Zero" in Africa's counterterrorism fight, senior U.S. officials warned of deepening links between the Islamic State and Boko Haram and prodded Chad's ruling strongman to introduce reforms for the sake of long-term stability.

But in a rare appearance before foreign journalists at his presidential palace, Chadian President Idriss Deby indicated he wouldn't help in the U.S.-backed effort to install a unity government in Libya, his country's northern neighbor, a former foe and an incubator for Muslim extremist groups.

The visit to Chad by America's U.N. envoy, Samantha Power, and top U.S. military officials such as Brig. Gen. Donald Bolduc, commander of special operations in Africa, highlights the country's precarious position dealing with a multitude of hostile militant groups and unstable neighboring governments. It also underscores the impoverished, land-locked country's growing geopolitical value.

Boko Haram has launched attacks on Chad's territory from its base in Nigeria to the southwest. The Islamic State and al-Qaida in the Islamic Maghreb lurk in chaotic and lawless Libya to the north. To the east is Sudan's Darfur region; to the south is the Central African Republic, still recovering from years of interethnic conflict

The Boko Haram-IS nexus may pose the greatest immediate threat. Although Boko Haram pledged its allegiance to the Islamic State last year, the operational connection has been unclear.

Bolduc said the groups clearly share "tactics, techniques and procedures," from the way they conduct complex ambushes and set improvised explosive devices like roadside bombs, to how they undertake high-profile attacks on hotels.

Suggesting the relationship is expanding, he said Chad on April 7 intercepted a "large cache of different types of weapons" sent from Libya and intended for the Lake Chad region. These included small arms, machine guns and rifles.

"You can, I think, draw a conclusion," Bolduc told reporters. The implication was that the weapons were sent by the Islamic State, which has established a foothold along Libya's Mediterranean coast, near the city of Sirte.

Given the range of threats here, he said the "Lake Chad Basin region is Ground Zero" in the fight against extremism in Africa.

Maj. Gen. L.O. Adeosun, head of the five-nation African force fighting Boko Haram, expressed a more muddied picture.

Adeosun cited "information," but not confirmation, of Islamic State members embedded within Boko Haram. But he said intelligence suggests Boko Haram still hasn't satisfied certain conditions set by the Islamic State for greater operational cooperation. He didn't elaborate.

At a briefing at the Multinational Joint Task Force's headquarters in Chad's capital, Adeosun showed reporters gruesome photos of the victims of Boko Haram attacks and the types of weapons employed.

One picture showed a bird with an explosive strapped on its back, demonstrating "a lot of ingenuity," Adeosun said.

Stressing the civilian aspect to defeating Boko Haram, a once indigenous Nigerian militant movement whose rebellion has morphed into a regional force, Power stressed the need to bolster economic development, job opportunities and political inclusiveness.

The message carried added weight, coming less than two weeks after Chad held elections that are widely expected to return Deby for a fifth term as president. Deby has led the country since 1990. Election results haven't yet been announced.

"We noted how far Chad has come from the dark days of dictatorship to today," Power said.

But she expressed displeasure with a "crackdown on freedom of protest" and a government decision to shut down the Internet and text messaging throughout Chad for several days around the time of the vote.

Deby rejected opposition claims that some 60 security forces who voted against him in the elections have since disappeared.

"There are no disappearances," he stated. "They will be presented on television, in front of the world."

As Power's delegation arrived in Chad, U.S. embassy staff warned accompanying journalists numerous times about rules prohibiting unauthorized photography in the country. They also told reporters not to ask Deby any questions.

But a somewhat reclusive Deby, who has survived at least a dozen coup plots and assassination attempts during his quarter-century in power, welcomed the opportunity to speak his mind.

The 63-year-old Deby, who seized power himself in a coup after helping Chad defeat Libya in the 1980s, said Washington and other powers were partly to blame for the Boko Haram-IS threat. He said they are destabilizing Libya through their effort to install a functioning government.

"The international community is imposing a unity government from outside Libya that will fail," Deby said.

-AP