Tower 22: What is the US outpost that was targeted by a deadly drone strike?

A little known US military desert outpost in the far reaches of Jordan has become the focus of international attention after a drone attack killed three American soldiers.

Sunday's strike against a facility - known as Tower 22 - has been blamed by Joe Biden's administration on an Iran-backed militant group.

Iran's foreign ministry has denied any involvement in the strike, which also injured 34 people.

The incident marks the latest flashpoint as tensions continue to grow across the Middle East, and pressure mounts on the US president to respond with retaliatory action.

So, what exactly is Tower 22 and why has the US stationed members of its armed forces there?

What is Tower 22?

Tower 22 is a US military base in northeastern Jordan. It sits near the demilitarised zone on the border between Jordan and Syria, and is six miles away from the Iraqi border.

The area of Jordan where the base is situated is known as Rukban, a vast arid region that once saw a refugee camp spring up on the Syrian side over the rise of the Islamic State (IS) group's so-called caliphate in 2014.

At its height, more than 100,000 people lived in the camp and - at the time - were blocked by Jordan from coming across into the kingdom over concerns about infiltration by the extremist group.

Those concerns grew out of a 2016 car bomb attack there, which killed seven Jordanian border guards

The camp has dwindled in the time since to some 7,500 people because of a lack of supplies reaching there, according to United Nations (UN) estimates.

How many troops are stationed there?

Tower 22 includes American engineering, aviation, logistics and security troops, with about 350 US Army and Air Force personnel deployed there.

Why are US troops stationed at Tower 22?

Tower 22's location offers a site for American forces to infiltrate and quietly leave Syria.

A small American garrison at al-Tanf, in Syria, is just 12 miles north of Tower 22, and is located along a Syrian highway leading into Iraq and the city of Mosul - once a prominent base of the IS group.

The US has long used Jordan, a kingdom bordering Iraq, Israel, the Palestinian territory of the occupied West Bank, Saudi Arabia and Syria, as a basing point. Some 3,000 American troops typically are stationed across Jordan.

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