Nigeria's military have shot dead a suspected media spokesman for Islamist terrorist group Boko Haram and another high-ranking member of the sect, an official told AFP.

Abul Qaqa, who was the group's spokesman, was shot dead during a shootout at a checkpoint in the outskirts of the city of Kano, while two field commanders were captured.

One of the commanders, who ran operations across a number of territories including Nigeria's capital Abuja, subsequently died of wounds sustained during the shooting.

"We carried out an operation early this morning in which we killed a media man [belonging to the] Boko Haram terrorists and arrested two field commanders of the sect," said Lieutenant Iweha Ikedichi, spokesman for a military task force.

An unnamed security sourced added that, following interrogation of the surviving field commander, the authorities have identified a house "used as an arsenal" by Boko Haram in the Rimin Kebe area of Kano, and found a large quantity of explosives.

The three suspects were entering Kano early in the morning of 17 September, along with a woman they were carrying to receive medical treatment. Thanks to intelligence information, the military were able to identify the Boko Haram members as they reached the checkpoint.

The alleged spokesman was said to have resisted arrest, prompting the shoot-out.

Since it stepped up its deadly operations in 2009, Boko Haram has reportedly been responsible for the deaths of at least 1,000 people.

Peace talks between the federal government and the sect, which wants to impose Sharia law across Nigeria, were halted when a Boko Haram spokesman claimed he could not trust the government.

Pressure has grown on US president Barack Obama to formally include Boko Haram on the terrorist watch list.