STRASBOURG, France -- The European Court of Human Rights ruled Thursday that the two 10-year-old boys convicted in Britain of the 1993 murder of a toddler had been treated unfairly because they were tried as adults.

The European court also said the rights of the two boys -- Robert Thompson and Jon Venables -- were violated by the decision of then British Home Secretary Michael Howard to increase their sentences -- from the eight-year term the judge gave -- to 15 years.

The court did not void Thompson's and Venables' sentences but put pressure on Britain to amend legal practices, such as the right of a government minister to set prison terms for minors or send juveniles accused of serious offenses to trial in an adult court.

Thompson and Venables were found guilty of taking Jamie Bulger, 2, from a shopping center in the north England town of Bootle to a railway line, two miles away, where they killed him. They were identified from shopping center security videotapes.

The rights court is part of the Strasbourg-based Council of Europe, guardian of the 1952 European Convention of Human Rights that details basic human rights. Britain is a signatory of the treaty and accepts the court's jurisdiction.

The court cannot overturn the boys' convictions or order their release but the British government will now be obliged to review any practices deemed to be in breach of the European Convention on Human Rights.

Trial must have confused the young boys, court says

"The formality and ritual of the crown court must at times have seemed incomprehensible and intimidating for a child of 11," the rights court said in its ruling.

It added it was unlikely that, "given their immaturity and disturbed emotional state," Thompson and Venables could properly communicate with their lawyers even outside the courtroom.

Murdered child's mother criticizes ruling

The murdered toddler's mother, Denise Fergus, issued a statement in which she criticized the European court's decision and said she was calling on Britain's Home Secretary Jack Straw to challenge the ruling.

"The killers have slick lawyers and always get kid glove treatment but the British government should not allow a European court to dictate how we operate our legal system," Fergus said. "Even though they are evil, I have to accept the killers will be released one day. But they should serve nothing less than 15 years."

The Home Office did not comment on the court's decision and said Straw was "considering the ruling."

The Associated Press and Reuters contributed to this report.