LONDON (Reuters) - Britain will outlaw al Shabaab -- a Somali-based Islamist militant group which recently pledged allegiance to al Qaeda -- preventing it operating or seeking funds in the UK, the interior minister said on Monday.

"I have today laid an order which, subject to parliamentary approval, will proscribe Al Shabaab. Proscription is a tough but necessary power to tackle terrorism and is not a course of action we take lightly," Home Secretary Alan Johnson said.

"(Al Shabaab) is committed to violence in order to achieve its aims, deploys a host of terrorist tactics and has been implicated in attacks on Somali citizens," Johnson said.

Western security agencies say Somalia, which has not had an effective central government for nearly two decades, has become a safe haven for Islamist militants.

Al Shabaab, which controls large parts of south and central Somalia, said last month it had joined "the international jihad of al Qaeda" .

In January, Britain used a similar measure to ban a group called Islam4UK, a local Islamist organisation.

REUTERS