The threat of civil war in Yemen has stoked fears over the security of oil supplies through the Bab al-Mandab shipping lane, a vital energy gateway for Europe, Asia and the United States.
Here are some details about the key chokepoint:
WHAT IS THE BAB AL-MANDAB?
* In Arabic, Bab al-Mandab means "Gate of Tears" referring to the strait's precarious navigation.
* It is located between Yemen, Djibouti, and Eritrea, and connects the Red Sea with the Gulf of Aden and the Arabian Sea.
* The Strait of Bab al-Mandab is a chokepoint between the Horn of Africa and the Middle East, and a strategic link between the Mediterranean Sea and Indian Ocean.
-- Bab al-Mandab was the site for of a naval blockade of Israel by Egypt in the 1973 Yom Kippur War.
* The Bab al-Mandab is 18 miles wide at its narrowest point, making tanker traffic difficult and limited to two channels for inbound and outbound shipments.
-- The island of Perim divides the strait, creating the two channels: The eastern channel is called Alexander's Strait (Bab Iskender) and is 2 miles (3.2 km) wide. The western channel, Dact-el-Mayun, is 16 miles wide (25.6 km).
* Exports from the Gulf and Asia to the West must pass through Bab al-Mandab before entering the Suez Canal.
* Closure of the strait could keep tankers from the Persian Gulf from reaching the Suez Canal or Sumed Pipeline, diverting them around the southern tip of Africa. This would effectively engage spare tanker capacity, and add to transit time and cost.
* An estimated 3.2 million bbl/d flowed through this waterway in 2009 (vs. 4 million bbl/d in 2008) towards Europe, the United States, and Asia. The majority of traffic, about 1.8 million bbl/d, moved northbound through the Bab al-Mandab en route to the Suez/SUMED complex.
(Writing by David Cutler, London Editorial Reference Unit; Editing by Lin Noueihed)