SANAA, Yemen — The United States, Britain, France and Italy said Wednesday they were closing their embassies in Yemen following Shiite rebels seizing power there, highlighting the turmoil gripping the country as it marked the fourth anniversary of toppling its longtime autocratic ruler.

The embassy closures came as Houthi rebels, armed with Kalashnikov assault rifles and dressed in police uniforms and civilian clothes, patrolled the main boulevards of the capital, Sanaa, some in pickup trucks mounted with anti-aircraft guns.

Scattered protests could be seen in the city, with demonstrators denouncing the Houthis for taking power and dissolving parliament. Shops closed early and helicopters also hovered overhead.

Houthis attacked one demonstration, stabbing and beating protesters trying to reach the local United Nations office, witnesses said. The rebels detained a number of people as well, they said.

In the central city of Bayda, also held by the Houthis, the rebels dispersed another protest, wounding a coordinator of the anti-Houthi movement, witnesses said.

In Taiz, Yemen's most populous city and one not held by the rebels, thousands flocked to the streets to protest the group.

Early Wednesday morning, U.K. Minister for the Middle East Tobias Ellwood urged British citizens still in Yemen to "leave immediately" as the British Embassy evacuated its staff. This came as the State Department confirmed it closed the U.S. Embassy in Sanaa and evacuated its staff. The French Embassy said it would close Friday.

"The security situation in Yemen has continued to deteriorate over recent days," U.K. Minister for the Middle East Tobias Ellwood said. "Regrettably we now judge that our embassy staff and premises are at increased risk."

The diplomatic missions of many Arab Gulf countries opposing the Houthis already have evacuated their staff.

Yemen has been in crisis for months, since the Shiite Houthi rebels began their offensive in September. Earlier Tuesday, U.S. officials said the embassy closure would not affect counterterrorism operations against al-Qaida's Yemen branch, which America views as the world's most dangerous branch of the terror group.

The United Nations has been trying to broker talks between the Houthis and others in Yemen since the Shiite rebels dissolved parliament after earlier besieging the country's president, who later resigned while armed militants surrounded his home.

Abdel-Malek al-Houthi, who leads the Shiite rebels, warned his enemies Tuesday not to stand in his hard-line movement's way and denounced foreign governments for removing their diplomats.

"We will not accept pressures. They are of no use," al-Houthi said in speech broadcast on the rebel group's own al-Masseria TV network. "Whoever harms the interest of this country could see that their interests in this country are also harmed."

Al-Houthi made a series of similarly threatening but vague remarks, and offered no explanation for what specific retaliatory action he might have in mind.

The Houthis are traditionally based in northern Yemen bordering Saudi Arabia. Many link the Houthis to regional Shiite power Iran, though the rebels deny they are backed by the Islamic Republic.