Homes in Edinburgh with possible links to the terrorist group the Kurdistan Workers' Party (PKK) have been raided by police.

Properties on four streets across the city were searched for evidence relating to the Kurdish militia organisation.

STV News understands the properties were residential and not linked to businesses.

Formed in the late 1970s, the PKK has Marxist-Leninist roots and was blamed for bomb attacks in south east Turkey that killed three people, leaving several others injured.

The group, which is part of the ongoing war in Iraq and Syria, was created in a bid to form an independent Kurdish state within Turkey.

Officers made no arrests in the major investigation in Edinburgh.

A Police Scotland spokeswoman said: "On Wednesday, Police Scotland executed search warrants at a number of addresses in the Edinburgh area in connection with an ongoing investigation.

"We understand local communities may have concerns as a result of this activity but would like to reassure people that this activity was intelligence led and not in relation to any immediate threat or risk.

"No one was arrested or charged as a result of these searches and enquiries are continuing. As this is now a live investigation, Police Scotland is unable to comment further at this time."

The Turkish air force regularly carries out air strikes against PKK bases in mountainous northern Iraq. Its government has ruled out any negotiations until the group completely disarms.

The Police Scotland spokeswoman added: "Since 2001, the PKK has been a proscribed terrorist organisation in the UK.

"This means that membership of the PKK is a criminal offence within the UK, as is any attempt to support or fundraise on behalf of the PKK.

"If any member of the public has information in respect of this, or indeed any other terrorist activity, we would encourage them to report this to the police."