Calls grew in Turkey on Wednesday to shut down a controversial gold mine as hopes dimmed of rescuing nine workers trapped by a massive landslide that rolled over their open pit.
Officials on Wednesday also reported the arrest of four people, including the open pit's field manager, in the opening stages of their investigation into the accident.
Hundreds of rescuers have been searching through a cyanide-laced field in eastern Turkey since Tuesday, when 10 million cubic metres of sludge suddenly crashed down from a gully.
Turkey's Union of Chambers of Engineers and Architects urged the government to shut down the mine "immediately", saying its past warning about a looming disaster had gone unheeded.
"All those responsible for the disaster should be held accountable before the judiciary," it said in a statement.
"All environmental impact reports should be cancelled and the plant should be closed immediately."
Environmentalists fear that cyanide and sulphuric acid used in the gold extraction process could spread into the Euphrates River, which runs from Turkey to neighbouring Syria and Iraq.
Turkey's environmental ministry said it had sealed off a stream running from the pit to the Euphrates as a precaution, adding that no polluting leaks had been detected so far.
But the Ilic Nature and Environment Platform, a local pressure group, said the stream had already mixed with the Euphrates.
"Don't seal off (the stream), seal off the mine," the group said.
Environmental advocates and local officials sought to shut down the open pit mine after a 2022 cyanide leak caused by a burst pipe.
The plant closed for a few months but then re-opened after its operator paid a fine, prompting an outcry from Turkey's opposition parties.
A Turkish court then fined the company 16.5 million Turkish liras ($540,000 at the current exchange rate), the maximum according to Turkish media.
But no further action was taken against the mine and a local push to shut it down failed.
The mine is run by private company Anagold, which has been extracting gold in the region since 2010.
Eighty percent of Anagold is owned by the Denver-based SSR Mining, and 20 percent by Lidya Mining.
SSR Mining's stocks sharply fell sharply on Tuesday.