A Bahrain appeals court has upheld jail terms of up to 15 years for 17 Shias convicted over attacks on police in the unrest-hit country, a judicial source said Tuesday.

The Manama court, which delivered the verdicts on Monday, also reduced by seven years sentences for three other defendants in the same case, the source said.

The group of Shias were tried on charges of attempting to murder police, carrying out arson attacks on their vehicles, causing public disturbance and possessing Molotov cocktails.

The charges followed a firebomb attack in February 2012 on a police station in Sitra, a Shia-populated village near Manama, that left one policeman injured and the front of the station damaged.

It came a year after Shia-led protests broke out against Bahrain's Sunni rulers, in an uprising to demand a democratic reforms that was crushed in a month.

Strategically located across the Gulf from Shia Iran, Bahrain is home to the US Navy's Fifth Fleet and is an offshore financial and services centre for its oil-rich Gulf Arab neighbours.

At least 89 people have been killed since the protests began, according to the International Federation for Human Rights.