U.S. closes Yemen embassy

Police troopers secure the entrance of the U.S. embassy in Sanaa, Yemen, February 11, 2015. REUTERS/Khaled Abdullah

An abandoned base for U.S. Marines near the U.S. embassy is seen in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Police troopers secure the entrance of the U.S. embassy in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

A general view of the U.S. embassy in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Houthi fighters stand on a truck as they secure a street where pro-Houthi protesters demonstrated to commemorate the fourth anniversary of the uprising that toppled former President Ali Abdullah Saleh in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Pro-Houthi protesters demonstrate to commemorate the fourth anniversary of the uprising that toppled former President Ali Abdullah Saleh in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Police troopers secure the entrance of the U.S. embassy in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

An abandoned base for U.S. Marines near the U.S. embassy is seen in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Police troopers secure the entrance of the U.S. embassy in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Pro-Houthi protesters demonstrate to commemorate the fourth anniversary of the uprising that toppled former President Ali Abdullah Saleh in Sanaa, February 11, 2015. REUTERS/Khaled Abdullah

Pro-Houthi protesters demonstrate to commemorate the fourth anniversary of the uprising that toppled former President Ali Abdullah Saleh in Sanaa, February 11, 2015. The banners read, 'Allah is the greatest. Death to America. Death to Israel. A curse on the Jews. Victory to Islam'. REUTERS/Khaled Abdullah