Sorry for the google translation:
A twin-engine plane disappeared Uruguayan tonight at the Rio de la Plata, minutes after takeoff from Motevideo toward the airport of Ezeiza. The apparatus, carrying two crew members, is searched intensively by air and sea. The plane, a twin turboprop owned by a Uruguayan airline, took off at 19.45 from the airport of Carrasco. Officials said the flight, lost contact just after 20.00. At that time, was south of the island of Flores. Reports of realized flight icing conditions at levels close to 1,500 meters. The aircraft was on a cargo flight, usually between two terminals. After the loss of contact, the Uruguayan authorities launched a search operation by air and sea. The deployment includes an aircraft Casa C-212 Aviocar and AS-365 Dauphin helicopter. And a Navy ship east.
So far several news sources are saying essentially the same. No word on the airline or airplane type. Some mention it was a scheduled cargo flight.
If they ditched the plane, even if the ditching itself had been successful the possibilities are small by now: Last night it was 0°C and the water temperature is about 15°C.