Peruvian prosecutors are seeking to bar the president and three other executives of Spanish oil firm Repsol SA’s local refinery from leaving Peru for 18 months while an investigation into an immense oil leak is conducted.

The government said last week that Repsol spilled some 6,000 barrels of oil into the ocean near the La Pampilla refinery on January 15, after unusual waves were triggered by a volcanic eruption near Tonga.

Peruvian President Pedro Castillo called it the biggest “ecological disaster” to affect the South American nation in recent years, as more than 180 hectares (445 acres) – equivalent to approximately 270 football fields – of beach and 713 hectares (1,762 acres) of sea were affected.

Dead seals, fish and birds have washed up on the shore covered in oil and fishing activities in the area have been suspended as an extensive clean-up operation involving hundreds of volunteers and workers was under way.

A judge will review the request by state prosecutors against the Repsol executives later on Thursday. Repsol representatives in Peru were not immediately available for comment, the Reuters news agency said.

Hundreds of volunteers and workers are racing against the clock to clean beaches after the spill from the Italian-flagged tanker “Mare Doricum”.

Repsol has said Peruvian authorities did not provide a tsunami warning and that the ship was continuing to unload oil to the refinery when the waves hit.

Castillo said last week that a committee would be formed to propose ways of dealing with the crisis, in keeping with national policies aimed at protecting the environment.

Prime Minister Mirtha Vasquez also said Repsol has promised to deliver a cleaning schedule, to incorporate local fishermen in the clean-up on beaches and to deliver food baskets to affected families.

A cleaner, Hector Fernandez, said the situation was “frustrating”.

“It is contaminating the entire beach and thus affects several people who come to spend the summer and the fishermen who work every day to earn their living with sweat, with fishing,” he told the AFP news agency.

Meanwhile, Peruvian authorities reported that a second, “relatively small” oil leak was registered on Tuesday during work on an underwater pipeline at the La Pampilla refinery – though the company denied it took place.

The Osinergmin supervisory agency of Peru’s environment ministry said “an estimated volume of eight barrels of crude oil … was recorded and brought under control”. Navy Captain Jesus Menacho said the new leak was “relatively small”.

Repsol denied there had been a new spill, saying in a statement on Wednesday there was “a controlled upwelling of remnants of the spill of January 15” during work on infrastructure 18 metres (60 feet) underwater.

“This upwelling was foreseen, so the containment barriers, absorbent elements and skimmers were already in place in the area as a safety measure. In this way, the hydrocarbon was controlled,” the company said.