Authorities said they have intensified a search Sunday for a small plane that disappeared off the coast of Venezuela with six people aboard, including the scion of Italy's Missoni fashion family.

The state-run AVN news agency, which said the family was briefed, reported no progress in locating the aircraft, which went missing late Friday on a flight from the Los Roques islands to Caracas.

The National Guard, backed by volunteers with private aircraft and boats, have so far covered more than 360 square nautical miles in a search and rescue operation involving more than 385 people, AVN said.

The plane was carrying Vittorio Missoni -- the son of the eponymous fashion label's founder Ottavio Missoni -- and his wife Maurizia Castiglioni, another Italian couple and two Venezuelan crew members.

Missoni runs the company known for its knitwear and iconic zigzag patterns with his siblings Luca and Angela. Vittorio is marketing director, his brother Luca is technical director and his sister Angela is the designer.

Shortly after news broke of his brother's disappearance, Luca went to Venezuela to get information first hand.

In the small town of Sumirago that houses Missoni's headquarters in northern Italy near Milan, company officials met as they awaited news about the plane.

Vittorio's parents and sister remained in the family home, according to Italian media.

Venezuelan interior ministry spokesman Jorge Galindo identified the other passengers on Twitter as Guido Foresti and Elda Scalvenzi. Pilot Hernan Merchan and copilot Juan Carlos Ferre Milano were also on board.

The Italian foreign ministry would only confirm that four Italian citizens had gone missing in Venezuela, without identifying them.

A similar disappearance took place exactly five years ago, on January 4, 2008.

At the time, a plane carrying 14 people, including eight Italians, went missing in the same area as it flew from Caracas to Los Roques. No trace of the aircraft or its passengers was ever found.

The Missoni fashion house was founded in 1953 by Ottavio Missoni and his wife Rosita. It now sells ready-to-wear attire for men, women and children, as well as haute couture and perfume.

Missoni has also created auto interiors for Mazda cars and designed interiors for two luxury hotels, in collaboration with the Rezidor Hotel Group.

In 2011, the label collaborated with Target, producing a wildly popular capsule collection that included everything from clothes to a bicycle. The retailer's website crashed for several hours due to high demand for the items.

Los Roques is an archipelago of 350 islands that attracts tourists from all over the world for its deep turquoise sea and the large number of exotic species that live there.