Egypt's Suez Canal chief said Saturday that "technical or human errors" could be behind the grounding of a huge container ship blocking the vital waterway, causing a backlog of over 300 vessels.
Osama Rabie, head of the Suez Canal Authority, told reporters that the ship could be afloat again by Sunday night.
The crisis has crippled global supply chains, forcing cargo firms to choose between waiting or the expensive option of rerouting vessels around the southern tip of Africa.
Officials had previously blamed 40-knot gusts and a sandstorm for the accident.
But Rabie said Saturday that "strong winds and weather factors" were not solely responsible, saying there "may have been technical or human errors".
Asked when the vessel might be freed, he sounded an optimistic note.
"We could finish today or tomorrow (Sunday), depending on the ship's responsiveness" to tides, he said.
Over 320 ships carrying billions of dollars-worth of cargo are now stalled at either end of the vital shipping lane linking Asia to Europe.
The 193-kilometre (120-mile) long canal from the Red Sea to the Mediterranean is vital for shipping between Asia and Europe, the alternative route around the Cape of Good Hope costing an additional 12 days at sea.
Egypt is losing some $12-14 million in revenue from the canal for each day it is closed, Rabie added.
- When will it move? -
The MV Ever Given, which is longer than four football fields, has been wedged diagonally across the canal since Tuesday, blocking it in both directions.
In one sign of the knock-on effects, Syrian authorities said Saturday they had been forced to ration already scarce fuel supplies.
The Suez suspension "has impacted oil imports to Syria and slowed arrival of a ship carrying fuel and oil products" from government ally Iran, Syria's oil ministry said.
And Romania's animal health agency said Saturday that 11 ships carrying livestock out of the country were affected by the blockage. NGO Animals International warned of a potential "tragedy" affecting some 130,000 animals.
Those involved in salvage efforts have given varying predictions about how long it could take to reopen the canal.
Yukito Higaki, president of Japanese firm Shoei Kisen which owns the MV Ever Given, told local media on Friday that the ship could be freed by late Saturday.
The executive director of Royal Boskalis, parent company of Smit Salvage which is in charge of the salvage operation, suggested the ship could be afloat again "at the start of next week".
Peter Berdowski said Friday that a crane was being set up to remove hundreds of containers from the ship's foredeck.
But Nick Sloane, a South African salvage master who was in charge of refloating Italy's Costa Concordia cruise liner, said that could involve "a very long delay".
The blockage has caused a huge backlog of ships at both the Red Sea and Mediterranean ends of the canal, causing major delays in the delivery of oil and other products.
Bernhard Schulte Shipmanagement (BSM) -- the ship's technical manager -- said efforts were focused on "dredging to remove sand and mud from around the port side of the vessel's bow".
Rabie told journalists Saturday that 14 tugboats had been deployed to help refloat the ship.
- Stakes 'too high' -
But the vessel with gross tonnage of 219,000 and deadweight of 199,000 has yet to budge, forcing global shipping giant Maersk and Germany's Hapag-Lloyd to look into re-routing around Africa.
Lloyd's List, a shipping data and news company, said Evergreen's Ever Greet had already done so, adding that the blockage was holding up an estimated $9.6 billion worth of cargo each day between Asia and Europe.
Liability for those losses could be hard to establish, according to Laleh Khalili, a politics professor at Queen Mary University of London.
The "fracturing of ownership and operation across different legal jurisdictions and national boundaries" makes it harder to assign responsibility for maritime accidents, she wrote in The Washington Post on Friday.
Suez traffic has been disrupted several times in the past, notably after Egypt nationalised the operating company in 1956.
That prompted an abortive invasion by Britain, France and Israel. Then during the Six Day War, Egypt imposed a blockade to prevent Israeli ships using the canal until 1975.
As efforts mount to free the Ever Given, salvage teams are hoping to take advantage of a spring high tide due to start Sunday night.
Plamen Natzkoff, an expert at VesselsValue, said teams would likely step up their efforts in the coming days to make the most of that opportunity.
"If they don't manage to dislodge it during that high tide, the next high tide is not there for another couple of weeks, and that becomes problematic," he said.
"The stakes are too high for it to take months."