In a statement carried on Thursday by the state-run Bahrain News Agency, BNA, the prosecutor's office said one defendant was jailed for 15 years and another for five years, while two others were sentenced to one year imprisonment each.
The four faced charges including "resisting police, possessing fire arms and ammunition for terrorist aims, attacking others and threatening to use fire arms,” the statement said, adding that the case goes back to last March.
Only last month, some 20 people were given jail terms in cases involving attacks on police and a bus, as well as a terrorist plot.
Anti-regime protesters have been holding rallies across Bahrain since mid-February 2011, calling on the ruling family to relinquish power.
The Al Khalifah regime is engaged in a harsh crackdown on dissent and also widespread discrimination against the country's Shiite-majority. Scores of people have been killed and hundreds of others injured or arrested in the tiny Persian Gulf kingdom, Press TV reported.
Human rights groups have repeatedly blasted Manama for handing down long-term sentences to anti-regime activists.
Bahrain, a key US ally in the Middle East, hosts the Fifth Fleet of the US Navy.