VIENNA (Reuters) - A Vienna court jailed two Austrian teenagers on Wednesday for plotting to kill police officers in a jihadist attack ordered by a Chechen member of Islamic State on a provincial police station, a court spokeswoman said.

A third man, a 22-year-old Chechen, had a previous jail sentence - imposed for robbery - extended by six months for his involvement in the case.

“The trio were convicted for being part of a terrorist group, for criminal conspiracy and for being part of a criminal organization,” the court spokeswoman said.

One of the Austrians was sentenced to 26 months in jail and the second, who also originally came from Chechnya, to 15 months, of which he must serve five months.

On Tuesday the court spokeswoman said a Chechen member of Islamic State known as Abu Nuuh had instructed one of the convicted Austrians in 2015 to murder police officers.

The assault was never carried out after authorities made public an anonymous tip about the plan.

The plot first came to light when the authorities found internet chats that one of the suspects had allegedly held with a German man accused in a separate case of plotting a jihadist bomb attack with the help of another Austrian teen.