Abuja - Nigeria has formally declared the Boko Haram Islamist sect and Ansaru, its suspected offshot, "terrorist" groups and issued a law to ban them, a presidential statement said on Tuesday.
"President Goodluck Jonathan has formally approved the proscription of Boko Haram and authorised the gazetting of an order declaring the group's activities illegal and acts of terrorism," said the statement from his office.
The ban "affects both Boko Haram (Jamaatu Ahlis-Sunna Liddaawati Wal Jihad) and another group - Jama'atu Ansarul Muslimina Fi Biladis Sudan", it said.
It officially brings the activities of both groups within the purview of the Terrorism Prevention Act and any persons associated with the two groups can now be legally prosecuted and sentenced to penalties specified in the law, the statement added.
The law prescribes a prison term of "not less than 20 years" for anybody who solicits or gives any form of support, including financial and logistics, to the groups.
Boko Haram has waged its insurgency since 2009, with an estimated 3,600 lives lost, including killings by the security forces.
Jonathan declared a state of emergency last month in three northern states -- Adamawa, Borno, Yobe -- the strongholds of the sect and launched ground and aerial attacks to flush out insurgents.
Ansaru last March claimed to have killed seven foreign hostages abducted from a construction site in the country's restive north the previous month, SITE Intelligence Group said.
There was however no confirmation from Nigerian authorities or the countries where the hostages were said to come from. An official from the construction company, Setraco, told AFP he was aware of the report but could not confirm it.
Police said the victims of the February 16 kidnapping in Bauchi state included four Lebanese, one Briton, a Greek citizen and an Italian.
But a company official later said the Middle Eastern hostages included two Lebanese and two Syrians.
The group is believed to have links of some kind with Al-Qaeda in the Islamic Maghreb, Al-Qaeda's north African wing.
Ansaru has been mentioned in connection with at least two other hostage-takings.
They included the May 2011 abductions of a Briton and an Italian working for a construction firm in Kebbi state, near the border with Niger. The victims were killed on March 8 last year in neighbouring Sokoto state during a botched rescue operation.
It also claimed the abduction last December of a French engineer in Katsina state, bordering Niger.
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