Oil from a Russian  trawler which was towed out to  sea to sink after catching fire in port is washing up on the beaches of Gran Canaria and  threatening  tourist spots across the Canary Islands. The Russian vessel Oleg Naydenov was carrying 1,400 metric tons of viscous fuel oil, when it caught fire in Las Palmas port on April 11. It was towed out to sea as a precaution and sank some 15 miles south of the island three days later. Clean up operation: Volunteers clear oil from the sunken Russian Trawler Naydenov on Los Seco beach, Gran Canaria . Spill: The  Oleg Naydenov was carrying 1,400 tonnes of fuel oil when it caught fire in Las Palmas port before being  towed it out to sea where it sank . Threat: An aerial picture shows part of the three mile long oil slick which is also threatening the Canary Islands of Tenerife and La Gomera . The Spanish government activated an environmental emergency alert and said one beach has been cleared of oil and clean-up operations were ongoing on three other beaches near the tourist town of Maspalomas. The government activated a level 2 alert after analyzing ocean current data from Spain's Oceanographic Institute, saying the slick that reached coastlines earlier in the week could affect vulnerable land. Level 2 is the second highest alert level. Environmental group Greenpeace  criticised the decision to tow the  vessel out to sea and has called on the Spanish government to dedicate more resources to the clean-up operation. Dedicated: A volunteer shows his oil-stained hands during the clean up operation on 'Los Seco' beach . Greenpeace has criticised the Spanish authorities for towing the trawler out to open sea after it caught fire in Los Palmas port . Volunteers taking part in the oil spill clean up . Oil spill clean up at 'Los Seco' beach, Gran Canaria . Estimates: According to Spanish officials the boat is still leaking between five and 10 litres of fuel an hour . Measures: The government activated a level two alert after analyzing ocean current data from Spain's Oceanographic Institute . A three mile slick of oil floating on the surface was photographed from the air last week and it is feared ocean currents could carry it onto the islands of Tenerife and La Gomera. Authorities estimated last week that the ship was currently leaking between five and 10 litres of fuel into the sea per hour. Development Ministry spokesman Julio Gomez said on Sunday that slicks were being monitored; a day after the government activated an alert, saying oil could damage the islands' vulnerable coasts. Greenpeace is calling on the Spanish government to dedicate more resources to the clean-up operation . Greenpeace released this picture of a dolphin with oil on its fin and have demanded Spanish authorities do more to control the spread of the oil which could hit Tenerife and La Gomera . An image taken by a robotic submarine shows the wreck of the Oleg Naydenov lying 2,700 meters down around 15 miles south of Gran Canaria . An unmanned remote-controlled submarine sent down 2,400 meters (7,900 feet) to survey the wreck . Greenpeace posted photographs of a dolphin partially coated in oil, while Spanish state television TVE broadcast images of workers cleaning a rocky beach that was stained black with oil. Red Cross spokesman Jose Antonio Rodriguez told The Associated Press that Veneguera beach on Gran Canaria island, a top European vacation spot, had been cleaned. An unmanned remote-controlled submarine sent down 2,400 meters (7,900 feet) to survey the wreck of the Russian trawler was inspecting to see if three holes in its hull could be blocked.
The Russian vessel caught fire in port and was towed out to sea to sink .
Three-mile oil slick also threatens tourist spots on Tenerife and La Gomera .
Clear-up operations ongoing on beaches near tourist town of Maspalomas .