COLOMBO, Sri Lanka — The Latest on the Easter attacks in Sri Lanka:

12:45 p.m.

Businesses in Colombo are advising staff to stay indoors until 2 p.m. because of a possible security threat and an ongoing search operation in the capital.

John Keells Holdings, the parent company of the Cinnamon Grand hotel, one of the sites stricken in the Easter Sunday bombings, sent an email to its staff on Thursday about the unspecified threat.

It was not immediately clear where the warning originated. A police spokesman was not available for comment.

A series of coordinated suicide bombings at churches and hotels in and around Colombo killed 359 people on Sunday. Police say a local extremist group was behind the attack.

10:20 a.m.

Australia's prime minister said one of the suicide bombers in the Sri Lanka Easter attacks had been in Australia years earlier.

Prime Minister Scott Morrison said the person had been in Australia on a student and a graduate skilled visa with a spouse and child visa as well. The individual left in early 2013.

Morrison told reporters Thursday the person's Australian link was part of an ongoing investigation and wouldn't comment further.

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Separately, a British security official has confirmed one of the bombers was believed to have studied in the U.K. between 2006 and 2007. The security official, who spoke on condition of anonymity because of the sensitive nature of the investigation, said British intelligence was not watching Abdul Lathief Jameel Mohamed during his stay in the country. His name was first reported by Sky News.

10 a.m.

Sri Lanka has banned drones and unmanned aircraft as authorities continue controlled detonations of suspicious items four days after a series of suicide bombing attacks killed more than 350 people in and around the capital of Colombo.

Sri Lanka's civil aviation authority said Thursday that it was taking the measure "in view of the existing security situation in the country."

Hobby drones have been used by militants in the past to carry explosives.

Iraqi forces learned that they are difficult to shoot down while driving out the Islamic State group from northern Iraq, where the extremists loaded drones with grenades or simple explosives to target their forces.

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Also Thursday Sri Lankan authorities detonated a suspicious item in a garbage dump in Pugoda, about 35 kilometers (22 miles) east of Colombo.

6 a.m.

Japan's Foreign Ministry has confirmed one Japanese national was killed and four others injured in the Easter bombings in Sri Lanka.

The body of the person who died was returned to Japan early Thursday.

Officials at Narita airport near Tokyo lowered their heads as the coffin, covered with blue tarp and a bouquet of white flowers on top, came out of the plane.

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Japanese media have identified the victim as 39-year-old Kaori Takahashi. The reports say she was having breakfast with her family at the Shangri-La hotel when she was killed and that her husband and a daughter were injured in the attack.

The Foreign Ministry has not released the identities of the dead and injured.

Sri Lankan police have said at least 359 people were killed and more than 500 wounded in Sunday's bombings, which mainly targeted churches and hotels. Most of the victims were Sri Lankan but more than 30 of the dead were foreigners.