Security forces blocked protesters trying to march to the capital Friday to call for a mass boycott of parliamentary elections planned for the following day, Reuters reported.

Thousands of supporters of the Shiite opposition Al-Wefaq society wave Bahraini flags during a rally Thursday. (HASAN JAMALI/ASSOCIATED PRESS)

Saturday's election is due to fill 18 parliamentary seats that have been vacant since members of the country's main Shia opposition party stepped down six months ago in protest of a government crackdown on protests. The opposition says they will boycott because the government has not done enough to address their concerns.

A boy holding a Bahraini flag participates in a rally held by the Shi'ite opposition party south of the capital Thursday. (HAMAD I MOHAMMED/REUTERS)

One Twitter user who has been tweeting on the protests shared this photo, said to be of tear gas, taken from outside his window:

Video footage emerged Friday that was said to show women confronting riot police:

Over the past several months, Bahrain has tried to tamp down international criticism over its handling of the unrest.

Bahrain's King Hamad bin Isa al-Khalifa, who was attending the U.N. General Assembly in New York on Thursday, said reforms were needed to “provide decent living conditions, security and tranquility in a society of peaceful coexistence.”