MANAMA, Bahrain (AP) -- Bahrain's highest court Monday upheld jail terms for 20 opposition figures -- including eight sentenced to life -- for alleged plots to "overthrow" the state in a decision likely to touch off more protests in the Gulf nation and bring renewed criticism from its Western allies.
The group includes a rights activist who staged a 110-day hunger strike last year to protest the verdicts, which critics have denounced as part of attempts to crush an Arab Spring-inspired uprising began nearly two years ago in the strategic island kingdom.
Authorities in Bahrain -- which is home to the U.S. Navy's 5th Fleet -- accuse Iran of encouraging the Shiite-led protests as a way to undermine Bahrain's pro-Western leadership and gain a key foothold on the doorstep of rival Saudi Arabia. Tehran has sharply criticized Bahrain's crackdowns, but denies it has any direct role with the opposition.
Bahrain's majority Shiites, who have led sporadic unrest in past decades, claim they face systematic discrimination at the hands of the Sunni monarchy. Bahrain's rulers have offered some reforms, including giving more powers to the elected parliament, but protest leaders say they fall short of demands for a role in key government affairs.
More than 55 people have died in the unrest since February 2011 and many opposition leaders and activists have been arrested, including the group of 20 charged with "plotting to overthrow" the ruling system by leading the protests.
Defense attorney Jalil al-Aradi said the high court refused to reconsider the sentences or convictions, which were originally handed down in 2011 by a military-led tribunal created under temporary martial law-style rules. The group has claimed they faced abuses while in custody.
Among the eight sentenced to life is rights activist Abdulhadi al-Khawaja, who staged a more than three-month hunger strike last year in protest. The other 12 have sentences ranging from five to 15 years, with seven convicted in absentia.
The case has brought international pressure on Bahrain, including efforts by Denmark to free al-Khawaja, who also holds Danish citizenship.
Scattered protests broke out in Bahrain shortly after the court decision, which could close all further appeal options.
"The Bahrain regime is pushing its human rights crisis closer to the edge," said Brian Dooley, director of the human rights defenders program at U.S.-based Human Rights First.
Last year, the official Bahrain News Agency said the charges include "plotting to overthrow the regime" and having "foreign intelligence contacts" -- a reference to Shiite powerhouse Iran and its proxy, Hezbollah in Lebanon. No clear evidence, however, has been presented to back Bahrain's allegations of direct Iranian aid to the opposition.
A government statement at the time said the court "provided all assurances of a fair trial" and allowed defense attorneys full access to the defendants. It also said they received "full medical care" in prison.
The crisis in Bahrain has pushed Washington into a difficult corner. It seeks to keep it crucial security and political bonds with Bahrain's leaders, but has increasingly condemned the ongoing violence and urged the country's rulers to open wide-ranging talks with the opposition.
In November, the U.S. State Department issued unusually harsh criticism of Bahrain for stripping citizenship of 31 activists and former opposition lawmakers for alleged links to protests.
Bahrain also faces other showdowns over jailed activists, including rights campaigner Nabeel Rajab whose prosecution has brought criticism from Washington.
Bahrain's main Shiite political group, Al Wefaq, claimed the courts are used a "tool to punish the opposition" and suggests that authorities are not serious about offers for a political dialogue to ease the tensions.
"It seemed there is no solution for the Bahraini crisis," said a statement by the group, "because there is no serious desire to solve this crisis."