PLAIN clothed security agents in their hundreds seized, Charles Okah, the younger brother to detained MEND leader, Henry Okah, in Apapa area of Lagos.
Charles Okah was arrested with some of his children according to family sources.
His brother, Henry Okah, who is currently detained by the South African police and undergoing trial for terror -related charges claimed in diary seized from him that Charles was faking his voice to negotiate with the Nigerian authorities in a "cease-fire" deal.
It is not clear if Charles was arrested over his brother's claims before South African magistrate or relating to the latest MEND threats which security sources said might have been traced to him.
Nigeria tightened security Saturday at the busy Abuja International Airport, a day after the militant group MEND threatened an imminent attack in the nation's capital, travellers said.
The officials, armed with bomb detectors, screened vehicles about 250 metres (800 feet) out on the airport access road, including conducting physical inspections of some vehicles.
"There was no such security measures in place at the airport three days ago," one traveller said.
The Movement for the Emancipation of the Niger Delta (MEND) threatened in a statement on Friday that a bomb attack was "imminent" in Abuja, which experienced twin car bombings two weeks ago in which at least 12 people died and several others injured..
The threat came in a statement that criticised the government's response to the October 1 Independence Day bombings.
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