Three men suspected of raising funds for the banned Tamil Tigers terrorist group were arrested yesterday.

Officers from Scotland Yard's Counter Terrorist Command swooped on addresses in Wales and London The raids were the latest development in a long-running police investigation aimed at flushing out sympathisers of the proscribed organisation.

The Tamil Tigers - or Liberation Tigers of Tamil Eelam (LTTE) - are responsible for three decades of guerrilla fighting in the island of Sri Lanka.

Government officials and senior police officers believe that large sums of money are collected in Britain to fund further attacks.

Tamil Tiger activists are also suspected of involvement in widespread credit card scams, fraud and extortion.

Police said the raids took place at residential and business properties in Newtown, Powys, Mitcham, south-west London, and Harrow, north-west London.

Two men, aged 39 and 46, were arrested at separate addresses in Powys, and a third, aged 33, was held in Mitcham, a spokesman said.

All three men were arrested on suspicion of the commission, preparation or instigation of acts of terrorism. They will be questioned at high security Paddington Green police station in central London.

Speaking about the operation, the spokesman said the suspected terrorism was not linked to al Qaeda-type activity or inspired terrorism.

He said: "It is in relation to support, procurement and fundraising for a proscribed organisation, the Liberation Tigers of Tamil Eelam."

A Dyfed Powys Police spokeswoman reassured the public that there was no cause for alarm.

She said searches of the properties may continue for "some time" and there will be disruption to neighbours.

"We would like to reassure our communities that arrests of this nature in the force area are rare and they should not be unduly alarmed," she added.

Tamil Tigers are responsible for terrorist attacks against armed forces and political targets in Sri Lanka, off the coast of southern India.

The rebels are fighting for autonomy for minority Tamils in the north and east of the island, claiming discrimination by the majority population.

More than 70,000 people have died in more than three decades of fighting and thousands have been forced to leave their homes.

The LTTE is thought to have power bases in both London and Paris, where sympathisers work to raise money for sophisticated weapons and other support.

More than 30 countries have proscribed the LTTE as a terrorist organisation, including the UK under the Terrorism Act 2000.

Two men, both from south London, have already appeared in court charged with terrorist offences in connection with the same operation.

One of the men is accused of arranging meetings of the Tamil Tigers and addressing an event in Hyde Park, central London.

He is also accused of amassing a hoard of military equipment including machetes, combat boots, camouflage clothes, spades and handcuffs. He denies the offences.