WASHINGTON, USA (AFP) — The leader of Nigeria's Christians called yesterday on the US to declare the Islamist group Boko Haram to be terrorists, but a US official said it was more important to address social inequalities.

In an unusually blunt appeal by a foreigner before the US Congress, the head of the main Christian body in religiously divided Nigeria said that a decision to blacklist three Boko Haram leaders as terrorists did not go far enough.

Ayo Oritsejafor, president of the Christian Association of Nigeria, said that the US move on June 21 was "the equivalent of designating (Osama) bin Laden a terrorist but failing to designate Al-Qaeda a terrorist organisation".

Oritsejafor said that the reluctance to brand Boko Haram as terrorists had emboldened the group, which is estimated to have killed more than 1,000 people since mid-2009 in attacks on Christian and government sites.

"By refusing to designate Boko Haram as a foreign terrorist organisation, the US is sending a very clear message, not just to the federal government of Nigeria, but to the world that the murder of innocent Christians and Muslims who reject Islamism — and I make a clear distinction here between Islam and Islamism — are acceptable losses," Oritsejafor said.

"It is hypocritical for the US and the international community to say that they believe in freedom and equality when their actions do not support those who are being persecuted," he told the House Foreign Affairs Committee.

Oritsejafor said Boko Haram sought "an end to Western influence and a removal of the Christian presence in Nigeria", telling the US lawmakers: "My people are dying every day."

But Johnnie Carson, the assistant secretary of state for African affairs, told the hearing that Boko Haram was not homogeneous and that most of the group had the goal of trying to "embarrass or discredit" the government.

A designation as a foreign terrorist organisation would trigger a full US government response against Boko Haram, freezing any assets it holds in the US and making support of the group a crime.

Carson said the terrorist designation made sense for the three leaders — Abubakar Shekau, Abubakar Adam Kambar and Khalid al-Barnawi — due to links to Al-Qaeda, but that it would be counterproductive to target the entire movement.

"It would serve to enhance their status, probably give them greater international notoriety amongst radical Islamic groups, probably lead to more recruiting and probably more assistance," Carson said.

Carson called instead for a "sophisticated and comprehensive" strategy of improving governance in Nigeria's largely Muslim north and curtailing human rights abuses.

"Boko Haram thrives because of social and economic problems in the north that the government must find a way of addressing," Carson said.