Manama: Bahraini authorities have detained four more opposition activists on security grounds, raising the stakes in the run-up to parliamentary elections after earlier arrests were criticised by rights groups.

The detentions bring to eight the number of activists and clerics arrested over the past week.

The detainees include Mohammad Saeed, a board member of the Bahrain Centre for Human Rights whose operations were formally suspended in 2004 but which continues to operate, Bahrain's state news agency said.

"The organisation's network aimed at compromising national security and harming the stability of the country," the news agency said late on Tuesday, citing a security source.

Violent protests

It said the group had funded violent protests in different parts of Bahrain. Bahraini government officials either declined to comment or could not be reached.

Bahrain's opposition activists complains of discrimination in jobs and services, an accusation the government denies.

Sectarian balance

The sectarian balance of Bahrain, home to the US Navy's Fifth Fleet, also concerns top oil exporter Saudi Arabia, which has a Shiite minority population in its eastern province adjacent to Bahrain.

Diplomats say the arrests appeared to be an effort to push the opposition to temper protests ahead of parliamentary elections due on October 23.

Bahrain has the only elected parliament in the Gulf Arab region besides Kuwait, even though its powers are limited as bills need to be approved by an upper house whose members are appointed by the king.

Bahrain earlier detained four other opposition activists, including Abdul Jalil Singace from the mainly Shiite Haq movement, saying they had formed a network to undermine the stability of the country.