An oil slick in the southern Indian Ocean is not linked to a missing Malaysian Airlines jet, Australia's search agency says.
The slick was found in a focus search area on Sunday, further raising hopes that the global effort to find flight MH370 might have narrowed in on the patch of ocean where the airliner went down on March 8, carrying 239 passengers and crew.
But late yesterday, the Joint Agency Coordination Centre (JACC) ruled out any connection.
"Preliminary analysis of the sample collected ... has confirmed that it is not aircraft engine oil or hydraulic fluid."
Despite the news the search will continue throughout the Easter long weekend, with both aerial and underwater sweeps planned.
A Bluefin-21 underwater drone is scanning the Indian Ocean seabed, more than 2000 kilometres northwest of Perth, but is yet to find the wreckage.
The JACC also refuted US Navy claims from earlier in the week that the drone would take up to two months to sweep the search area.
In its latest statement, it revealed that the underwater search area has been "significantly narrowed" in recent days.
The drone has also been cleared to reach depths of more than 4.5 kilometres, with a small but acceptable level of risk.
"This expansion of the operating parameters allows the Bluefin-21 to search the sea floor within the predicted limits of the current search area."
But there has been criticism of the Bluefin-21 system, which has to surface to download information for analysis.
Richard Gillespie, who led the search for aviation pioneer Amelia Earhart's plane in the Pacific Ocean has told CNN that the Bluefin-21 "didn't work for us".
The US Navy has offered Australia the use of its Orion-towed search system, which can send back real-time data.
Prime Minister Tony Abbott is confident the search is focused on the right area, based on acoustic signals detected by a pinger locator towed by an Australian Navy vessel.
He told the Wall Street Journal on Wednesday that the best leads would be exhausted in about a week.
"If we don't find wreckage, we stop, we regroup, we reconsider," he said.
Saturday will mark six weeks since the disappearance of flight MH370.