BUENOS AIRES : Argentina 's military on Saturday were continuing the search for the submarine ARA San Juan, which has been missing with 44 crew aboard for days.

There has been no contact with the submarine since Wednesday morning, according to the navy, prompting Buenos Aires to launch an air and sea search for the missing vessel.

"We will do what is necessary to find the submarine as soon as possible," President Mauricio Macri said on his Twitter account on Saturday.

The TR-1700 class diesel electric submarine had been returning from a routine mission to Ushuaia near the southernmost tip of South America, to its base at Mar del Plata, around 400 kilometers (240 miles) south of Buenos Aires. Among those on board is Argentina 's first female submarine officer, 35-year-old weapons officer Eliana Krawczyk.

The San Juan is one of three submarines in the Argentine fleet.

Sixty-five meters (213 feet) long and seven meters wide, it was built by Germany's Thyssen Nordseewerke and launched in 1983.

It underwent a re-fit between 2007 and 2014 to extend its usefulness by some 30 years.