LONDON, Nov 22 (Reuters) - Britain on Thursday banned a Nigeria-based Islamist group it said was aligned with al Qaeda as a minister said the oulawed organisation was probably responsible for the killing of a Briton and an Italian.
Britain's interior ministry described the group - Ansaru - as "a Nigeria-based terrorist organisation motivated by an anti-Nigerian government and anti-Western agenda".
The two men Britain believes the group murdered were Chris McManus, a Briton, and Franco Lamolinara, an Italian.
They were kidnapped in May last year near Nigeria's northwestern borders with Niger and Benin and their captors killed them during a British-Nigerian rescue mission in March this year.
"An order has been approved today by parliament which will proscribe Ansaru from midnight on Thursday evening, making membership of, and support for, the organisation a criminal offence," the interior ministry said in a statement.
It declined to say whether the group was connected to the deaths of McManus and Lamolinara.
However, Mark Harper, a minister of state for immigration, told parliament the group was probably responsible.
"It is believed to be responsible for the murders of British national, Christopher McManus, and his Italian co-worker Franco Lamolinara, in March 2012," he said.
At the time of their deaths, an official at Nigeria's State Security Service said the captors belonged to a faction of Islamist sect Boko Haram, which has targeted Nigerian security and government officials as well as churches and mosques.
A purported spokesman for the group denied any part in the kidnappings at the time.
Ansaru's full name is Jama'atu Ansarul Musilimina Fi Biladis Sudan, which translates as "Vanguards for the Protection of Muslims in Black Africa".