Hundreds of Shi'ites in Saudi Arabia rallied in two towns in the kingdom's eastern province of Qatif, where they demanded the release of prisoners and the withdrawal of Saudi troops from Bahrain.
Some demonstrators waved Bahraini flags on Friday as they took to the streets in a show of solidarity with Bahrain's Shi'ite majority, which has been demanding reforms from the country's Sunni-led government.
Earlier this month, hundreds of Saudi soldiers and police officers from the United Arab Emirates entered Bahrain at the request of the the country's King Hamad bin Isa al-Khalifa.
King Hamad authorized the entry so that the foreign forces could help him protect government buildings after pro-reform demonstrators paralyzed the financial district in Manama.
The Saudi government has announced a number of concessions in recent weeks, in an apparent bid to hold off the kind of political uprisings sweeping through much of the Middle East.
Earlier this week, the government said voting will take place in April in what will be only the second nationwide municipal election in the kingdom. The first polling took place in 2005 and only included Saudi men.
Saudi King Abdullah also issued royal decrees this month to increase the minimum wage for state workers, spend billions of dollars on new housing and add thousands of jobs to the security and interior sectors.
Some information for this report was provided by AP and Reuters.