"A sea patrol supported by units from the navy and the National Guard at dawn on Friday rescued 487 clandestine migrants of various Arab, Asian and African nationalities," the defence ministry said. They included 93 children and 13 women.

The vessel had set off from neighbouring Libya and was heading towards Europe when it was intercepted off the Tunisian city of Sfax, it said.

The ministry published photos of a vessel carrying dozens of people, with many others swimming next to it.

Libya, already a major route for migrants seeking to reach Europe, saw a surge in departures as it plunged into lawlessness after a 2011 NATO-backed revolt.

Around half of those intercepted on Friday were Egyptians or Bangladeshis, along with dozens of Syrians and Moroccans and smaller numbers of Eritreans and Sudanese, the ministry said.

The interception was the latest in a string of similar operations to thwart sea crossings or to rescue migrants in unseaworthy boats.

Tunisian authorities said over the weekend that they had intercepted more than 200 migrants as they tried to reach the Italian coast.

That came after the coastguard said it had blocked six departure attempts and rescued 125 Europe-bound migrants in late October.

Earlier that month, four Tunisian migrants died and 19 others went missing after their boat capsized.

While it does not suffer the lawlessness of Libya, Tunisia is another key departure point for migrants hoping to reach Europe.

The Italian island of Lampedusa is located just 140 kilometres (less than 90 miles) from Tunisian shores.