Authorities in Bahrain on Saturday expelled two foreign human rights activists, accusing them of violating tourist visa rules by joining anti-government demonstrations in the Persian Gulf kingdom.

The authorities said the two women were ordered out of the country after being arrested during a protest in the capital Manama, ahead of Tuesday's one-year anniversary of the beginning of the Shi'ite-led uprising.

The Associated Press quoted the president of the Bahrain Center for Human Rights, Nabeel Rajab, as saying the pair are U.S. citizens.

Tensions have run high in Bahrain as the opposition and activists prepare to commemorate the protests aimed at breaking the Sunni minority's hold on power in the Shi'ite majority nation.

The government crushed the pro-democracy protests last March with help from Saudi troops, but smaller confrontations between opposition protesters and security forces have continued.