Israel has sent a team of investigators to Greece to check a ship believed to have caused an oil spill covering much of Israel’s shoreline with tar, the vessel reportedly having passed about 30 miles offshore.

“We will … use all means until we find the environmental perpetrator responsible for the pollution,” Environmental Protection Minister Gila Gamliel said in a statement as environmental groups warned of an eco-disaster from the oil, said Reuters

Israel did not provide details of the ship. A Greek Coast Guard official who declined to be named said Greece hadn’t received any official request from Israel to inspect a Greek ship or if it would be allowed.

Volunteers, and thousands of soldiers, have been gathering daily on Israel’s beaches to remove the clumps of sticky black tar, which have also been washing up in southern Lebanon, the news site said.

The Israeli newspaper Haaretz said the ministry was, however, working in cooperation with Greece’s Foreign Ministry with Gamliel saying a single ship was responsible for the spill.

The director of the ministry’s Marine and Coastal Environmental Division, Rani Amir, said that the source is one of several suspected ships, but that the ministry has excluded five ships that had initially come under suspicion.

The Health Minister earlier banned the sale of fish and other marine life caught off the coast until further notice.

Gamliel said Israel does not have authority to stop ships in the open sea. Amir added that the ministry had asked for a gag order in the case due to concern that the operator of the polluting ship would seek to obstruct the investigation.

Researchers at the Hebrew University of Jerusalem said samples they collected from several beaches all have been found to be crude oil, the paper’s report added.

Prof. Alon Amrani of the university's Institute of Earth Sciences said the team had determined it likely wasn’t ship fuel that was the source though, adding to the mystery of what happened.

Animals were found covered with tar, including a few birds and nine sea turtles. Four of the turtles died, while the others were taken to the National Sea Turtle Rescue Center at Mikhmoret between Tel Aviv and Haifa, the report also added.