A European Commission consular Web site issued an advisory list for travelers from the 27 EU nations Friday, EUobserver reports.
Yemen exceeds even Libya in the danger ratings. Third is Iraq, followed by Bahrain, Iran, Syria, Saudi Arabia, Lebanon, Algeria, Egypt, Tunisia and Israel.
At the bottom of the list, only some areas are considered risky in Morocco, Kuwait, Jordan, Qatar, Oman and the United Arab Emirates.
Yemeni President Ali Abdullah Saleh has been under pressure to resign for months, and more than 100 people have been killed during protests in recent weeks. France and Britain have warned their citizens anew to "leave immediately" thanks to "a rapid deterioration in the security situation."
Besides being on the verge of revolution, Yemen also poses dangers to Westerners from al-Qaida groups and regional rebels.
In Syria, President Bashar al-Assad, while under pressure, is not threatened by foreign intervention, unlike Libya's Moammar Gadhafi, and European visitors are normally welcomed by local people.