Gibraltar chief minister Fabian Picardo has had reportedly received death tweets from Spanish Twitter users, making him the second politician targeted via the micro-blogging service.

According to Picardo, the death threat followed after his criticism of the Spanish government’s actions, which claimed to have extended delays at the border with the British Overseas Territory.

The Spanish Twitter attack comes after the creation of an artificial reef by the Gibraltar authorities, which Madrid claims would affect fishing in the area.

Picardo said: "I think social media is a great thing, but it also has a very negative aspect to it, which is people can use the cloak of anonymity to insult people and to say things that reasonable human beings don’t say about each other."

"I have had some extreme reactions to things I say," the Gibraltar CM added.

"I have even had death threats against my family by Twitter."

During early August, female journalists have received bomb threats on Twitter, which reportedly followed a petition seeking the micro-blogging site to enhance its processes of handling threats.

Twitter has also revealed plans to incorporate a button for reporting abuse within every tweet -a feature which is currently being offered on its iPhone app.