Another of the Middle East nations facing protests against its government, Yemen, has experienced wider problems, including a violent crackdown on protesters and a defection by key military officials.

The country, run by President Ali Abdullah Saleh, a key ally of the United States, has been the scene for violent oppositions in the past, including a civil war in 1994, in which government troops prevented a secession attempt from the southern part of the country.

However, in the wake of similar protest movements in other African and Middle Eastern countries, the Yemeni protest movement gained three powerful new allies, including Maj. Gen. Ali Mohsen al-Ahmar, commander of the Army's 1st Armored Division and previously a strong supporter of Saleh. Al-Ahmar immediately turned rank, installing tanks and armored vehicles in the main square of Sanaa, the capital city, in defense of protesters who have demonstrated for weeks in support of Saleh's resignation, the president's recent firing of his entire Cabinet notwithstanding. The defecting general said he could not endorse a recent crackdown, during which 40 people were killed. Saleh has announced that he would not seek re-election when his current term runs out in 2013. Protesters would remember a similar pledge in 2002, which was followed by an abrupt reversal and a subsequent re-election by a wide margin.

Al-Ahmar also announced that he had sent tanks to surround the Defense Ministry, the Central Bank, and the state television headquarters. Two other senior army commanders announced their defections, as did the country's ambassadors to Egypt and the Arab League.

Eleven members of the parliament have also resigned.

Echoes of the sectarian conflict in Bahrain can be found in Yemen as well, as President Saleh and much of northern Yemen are Shiite but the southern part of the country is Sunni Muslim.

Saleh, who has ruled the country for 32 years, has seen a key ally, Saddam Hussein, removed from power in Iraq and has also been a key supporter of Iran and its nuclear program.