JAKARTA, Indonesia -- Indonesia's highest court has upheld the death sentence for a British woman convicted of smuggling $2.5 million worth of cocaine into the resort island of Bali, a court official said Friday.

The three-judge panel unanimously rejected Lindsay Sandiford's appeal on Thursday, said Supreme Court spokesman Ridwan Mansur.

Sandiford, 57, was arrested last year when 3.8 kilograms (8.4 pounds) of cocaine was discovered stuffed inside the lining of her luggage at Bali's airport. During the trial, she said she was forced to carry the drugs by a gang that threatened to hurt her children.

She was found guilty in January by a district court and sentenced to face a firing squad. She lost an appeal three months later when the Bali High Court upheld the lower court's ruling.

Prosecutors had initially sought 15 years in prison for Sandiford, but the court surprised many by issuing a death sentence. She still has the opportunity under Indonesian law to seek a judicial review of her case and also appeal for presidential clemency.

"We are aware that Lindsay Sandiford's appeal to the Indonesian Supreme Court has been denied,'' Adam Rutland, spokesman for the British embassy in Jakarta, said in an email. "In line with our strong opposition to the death penalty in all circumstances, we will consider how to support any application for judicial review or clemency that Lindsay Sandiford chooses to make.''

Four other defendants -- three Britons and an Indian -- connected to the case were sentenced to jail terms ranging from one to six years.

Indonesia has strict anti-drug laws and most of the more than 40 foreigners on its death row were convicted on drug charges.

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  • In this photograph taken on January 22, 2013 convicted drug smuggler, British grandmother Lindsay Sandiford, is confined in a holding cell after the court handed its verdict in Denpasar on the resort island of Bali. (SONNY TUMBELAKA/AFP/Getty Images)

  • In this Jan. 7, 2013 file photo, Lindsay June Sandiford of Britain sits at a courthouse during her trial in Denpasar, Bali island, Indonesia. (AP Photo/Firdia Lisnawati, File)

  • In this Jan. 7, 2013, file photo, Lindsay June Sandiford of Britain fans herself as she arrives at the courthouse for a hearing in Denpasar, Bali island, Indonesia. (AP Photo/Firdia Lisnawati, File)

  • Lindsay June Sandiford of Britain, center, is escorted to a holding cell after her verdict was announced at a courthouse in Denpasar, Bali island, Indonesia, Tuesday, Jan. 22, 2013. (AP Photo/Firdia Lisnawati)

  • Lindsay June Sandiford of Britain, right, stands next to her interpreter as her verdict is announced at a courthouse, in Denpasar, Bali island, Indonesia, Tuesday, Jan. 22, 2013. (AP Photo/Firdia Lisnawati)

  • Lindsay June Sandiford of Britain, right, listens to her interpreter during her sentencing at a courthouse, in Denpasar, Bali island, Indonesia, Tuesday, Jan. 22, 2013. (AP Photo/Firdia Lisnawati)

  • In this Jan. 3, 2013 file photo, Lindsay June Sandiford of Britain, covers her face from the camera as she sits in the dock during her trial at the Denpasar District Court in Denpasar, Bali island, Indonesia. (AP Photo/Firdia Lisnawati, File)

  • Lindsay Sandiford of Britain, center, arrives at a courthouse in Denpasar, Bali island, Indonesia, Monday, Jan. 7, 2013. (AP Photo/Firdia Lisnawati)

  • Lindsay June Sandiford of Britain, right, listens to her interpreter as her verdict is announced at a courthouse, in Denpasar, Bali island, Indonesia, Tuesday, Jan. 22, 2013. (AP Photo/Firdia Lisnawati)

  • British citizen Lindsay Sandiford listens to a witness during her trial at a court room in Denpasar, Bali, Indonesia on Wednesday, Nov. 28, 2012. (AP Photo/Firdia Lisnawati)

  • British citizen Lindsay Sandiford, left, listens to her Indonesian lawyer Ersa Karo Karo, right, in a courtroom during her trial in Denpasar, Bali, Indonesia Wednesday, Oct. 31, 2012. (AP Photo/Firdia Lisnawati)