(CNN) -- Boats, helicopters and divers were searching off the coast of Venezuela Sunday for a director of Italy's famed Missoni fashion house and five others who haven't been heard from in more than two days.
Venezuelan officials said search efforts to locate the small plane Vittorio Missoni and his wife were flying in were intensifying. Authorities say the plane last made contact about 10 nautical miles from shore on Friday.
"All the organizations involved will not diminish the intensity of the search and also will not discard any hypothesis that could lead us the the location of the plane," Venezuela's air transportation ministry said in a statement Sunday.
More than 385 people were involved in the search, including military personnel, divers, civil protection search teams and volunteers, the ministry said.
Italy's ANSA news agency reported that rough seas were complicating the investigation.
Vittorio Missoni, 58, runs the fashion house with his siblings, Luca and Angela.
The company Missoni confirmed in a statement Saturday that Vittorio Missoni was on the plane with his wife.
"The small plane they were traveling on has disappeared. This is all the information currently available," the company statement said.
The plane left Los Roques, an archipelago and resort, Friday morning bound for the international airport outside Caracas, about 90 miles away, Venezuelan Interior Minister Nestor Reverol Torres said.
Venezuelan authorities said four Italian tourists and two crew members were onboard.
Missoni, which boasts such celebrity clients as Katie Holmes, Cameron Diaz and Nicole Richie, is a high-end fashion label known for its patterned knitwear and signature zigzag stripe.
The private company, based in Milan, has estimated annual sales of between $75 million and $100 million.
The brand, first created in 1953 as a knitwear workshop in Gallarte, Italy, has expanded from apparel to housewares, a fragrance line and a chain of hotels.
Stefano Tonchi, editor-in-chief of W magazine, called the Missonis "one of the most important Italian fashion families," crediting their move to Milan in the late 1960s with helping make the northern Italian city the fashion hub it is today.
Vittorio Missoni and his siblings took over the brand in 1996 with an eye toward marketing to a younger consumer.
The fashion house partnered with Target in 2011 to produce a more budget-friendly collection for the discount retailer, which caused Target's website to crash due to the high demand.
CNN's Susannah Palk and Laura Smith-Spark reported from London, and Catherine E. Shoichet, Marilia Brocchetto, Sarah Aarthun, Alexander Hunter, Mitra Mobasherat, Chandrika Lakshminarayan and Esprit Smith from Atlanta.