MANAMA, Bahrain — ­Bahrain’s highest court Monday upheld jail terms for 20 ­opposition figures — including eight sentenced to life — for alleged plots to ‘‘overthrow’’ the state. The decision is likely to touch off more protests in the Gulf nation and renew 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 that began nearly two years ago in the strategic island kingdom.