Hamas accused Western and Arab spy agencies on Saturday of operating in the Gaza Strip and said it had a list of alleged collaborators.

"The Gaza Strip is swarming with Western intelligence agencies, such as the American, British, French and German services," said Mohammed Lafi, an internal security chief, quoted on the Hamas interior ministry website.

"They all target Gaza and Hamas," he said, while also pointing a finger at unnamed Arab intelligence services.

The Hamas official, whose Islamist movement rules Gaza, said the security services had "a list of collaborators who will be arrested once the time for them to repent has run out."

Some have already been arrested and "half of them have confessed to being collaborators," said Lafi, who also cautioned against Palestinian journalists feeding information to foreign correspondents and institutions.

Hamas, branded a terrorist organisation by the Unites States and European Union, on March 12 set a one-month ultimatum for alleged Palestinian "collaborators" with Israel to surrender in return for leniency.