The nation was effectively shut down, with workers in the capital unable to pass checkpoints or too scared to venture out, while banks and other key institutions did not open.
Military steps in during Bahrain protests
MANAMA // Armed patrols prowled neighbourhoods and tanks appeared in the streets for the first time on Thursday after riot police with tear gas and clubs drove protesters from a main square. Medical officials said four people were killed.
Police cars with flashing blue lights encircled Pearl Square, the site of the rallies since Monday. Barbed wire was set up on streets leading to the square, where police cleaned up flattened protest tents and trampled banners. The interior ministry declared the protest camp "illegal" and warned Bahrainis to stay off the streets.
The nation was effectively shut down since workers in the capital could not pass checkpoints or were too scared to venture out. Banks and other key institutions did not open.
The protesters' demands include more jobs, better housing and the freeing of political prisoners. They also want the government to address deep grievances held by the country's majority Shiites who claim they face discrimination and are effectively blocked from key roles in public service and the military.
Hospital officials, speaking on condition of anonymity because they were not authorised to talk to the media, said four people were killed early on Thursday. Wounded streamed by the dozens into Salmaniya medical centre, the main state-run hospital in Manama, with serious gaping wounds, broken bones and respiratory problems from the tear gas.
Tanks and armored personnel carriers were seen on some streets - the first sign of military involvement in the crisis - and authorities send a text message to cell phones that said: "The Ministry of the Interior warns all citizens and residents not to leave the house due to potential conflict in all areas of Bahrain."
* Associated Press