SANAA, Yemen — While Friday prayer services were underway at a mosque near the US Embassy compound in Sanaa Friday, officers in camouflage uniforms were at-the-ready, clutching their batons.

After protesters stormed the embassy on Thursday, authorities blocked several streets in anticipation of more riots in Yemen, which followed similar ones in Egypt, Libya, Tunisia and other parts of the region. As the protests continued, the Pentagon took precaution and sent 50 marines to Yemen Friday to boost security at the US embassy. The unrest erupted after a cheaply-made, obscure anti-Islam movie trailer went viral earlier this week, though most protesters admitted to not having seen the clip.

Along the Siteen highway, across town from the US Embassy, crowds gathered to offer their prayers right in the road, which has been a weekly tradition since Yemen's revolution erupted last year. But once the services ended, some worshippers marched along the road, unfurling banners in Arabic, reading, "We are here, Muhammad," and "O community of Muhammed, your prophet is insulted." Khaki-clad soldiers in red berets looked on. Women in niqab, the black face-veil, bore signs on the crown of their heads expressing solidarity with their Prophet.

A group of young men held homemade posters with proclamations written in marker. In English, one of their signs said: "This is not freedom of speech or expression! It is offense on Prophet Mohammed! It is untruth! No to lie at distortion. Prophet of Allah: Mohammed." Among those who helped draft the signs was 25-year-old Dhaafar Al-Dahmani, who along with his friends carried Syrian flags. Dressed in a stylish ivy cap, plaid shirt and jeans, the engineering student said he was upset about the film, Innocence of Muslims, for showing the Prophet in a negative light.