ADEN/DUBAI: Saudi Arabia has temporarily shut down its East-West oil pipeline after the important oil route was hit by an aerial attack, as the war in the Middle East continues to spread.

The world's biggest crude oil exporter closed the pipeline as a precaution after a drone attack that Saudi Arabia and Iraq said had come from Iraq. Iranian-backed armed groups operate in parts of Iraq. In response to the attack, Iraq dismissed a military commander on September 12.

The 1,200-kilometer pipeline crosses the Arabian Peninsula, allowing Saudi Arabia to export oil without relying entirely on tankers transiting the Strait of Hormuz. Shipping through the strategic waterway has slowed sharply because of the war between the United States and Iran.

Saudi Arabia's energy ministry said the pipeline was closed as a safety measure. Shipping companies and analysts estimated that it had carried between four and five million barrels of oil per day in recent months. That is equal to about four to five percent of the world's total oil supply.

The attack came as Iran-aligned Houthi fighters in Yemen strengthened their position around the Red Sea. The disruption in both the Red Sea and the Strait of Hormuz has put pressure on energy supplies on both sides of the Arabian Peninsula. Global oil prices have risen above US$100 a barrel.

It was not immediately known who carried out the attack. Satellite images showed black smoke rising from an area of the pipeline south of Medina. The Saudi foreign ministry said some people were injured and the pipeline was damaged, but it did not provide details on the impact on oil exports.

The Iraqi military commander who was removed from his post had been responsible for operations in Maysan province, according to the Iraqi prime minister's office. Maysan borders Iran in southeastern Iraq and has long been considered an area where Iranian-backed Shi'ite militias have strong influence.

Saudi Arabia has so far decided not to retaliate, following a request from the Iraqi prime minister. However, the Saudi foreign ministry said the kingdom reserved the right to "take all measures necessary" to protect its interests. Iraq's government also condemned the attacks.

The International Energy Agency said that Saudi crude oil supplies had fallen to their lowest level in more than 30 years. It said the decline was partly linked to attacks on ships passing through the Bab el-Mandeb by groups linked to the Houthis.

As a precaution, Iraq also ordered the closure of the Shalamcheh border crossing with Iran, according to two security sources. The crossing is an important route for food imports from Iran, including vegetables.

The two sources said a large operation was underway to identify those behind the pipeline attack.

If the Houthis take control of the Bab el-Mandeb Strait, Iran could gain an important strategic advantage in its war with the United States.

Yemeni government forces indicated that they would attempt to recapture territory taken by the Houthis. The fighters have survived years of heavy Saudi airstrikes during Yemen's civil war and launched a rapid offensive along the Red Sea coast this week.