SANA, Yemen — The Houthi militiamen who effectively rule Yemen were increasingly isolated Wednesday as several Western countries joined the United States in closing their embassies here, despite few signs of deteriorating security in the streets.

Some international organizations appeared to be reducing their staffs as well, and the World Bank, which provides more than $1.1 billion in support to Yemen, had only a guard force on duty on Wednesday at its offices.

Many saw the move as intended to pressure Yemen’s power brokers to come to an agreement. Although the embassies cited security concerns as the reason behind the closings, they came amid relative calm in Sana, the capital, even on the anniversary of its Arab Spring revolution, with peaceful pro- and anti-Houthi demonstrations.

The British and American embassies in Sana were closed Wednesday, with the last diplomats from both embassies withdrawn. The German Embassy was also closed, a security official said, although its diplomats had not yet left. France urged all its citizens in Yemen to leave and said that the embassy would close Friday.