Jordan on Sunday announced the start of military exercises involving more than 8,000 soldiers and observers from 19 different countries, but insisted the manoeuvres were unrelated to the conflict in neighbouring Syria.
Around 4,500 US troops and 3,000 Jordanian soldiers are taking part in the air, land and sea "Eager Lion 2013" exercise, which lasts until June 20.
"Eager Lion this year will focus on irregular warfare, like combatting terrorism and insurgency," Major General Awni el-Edwan, the Jordan Armed Forces' operations chief of staff, told reporters.
He was speaking at a joint news conference with Major General Robert G. Catalanotti of the US Army Central Command.
"The exercises have nothing to do with any regional developments around Jordan," Edwan said, referring to the conflict in Syria.
The United States has said it was sending a Patriot missile battery and F-16 fighters to Jordan for Eager Lion, and may keep them there to counter the threat posed by the Syrian civil war.
"Patriot missiles and F-16 fighters are taking part in the drill in a pure military context. Keeping them in Jordan needs a political decision that we, military people, do not interfere in," Edwan said, without elaborating.
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He added that the exercises will take place in Jordan's central and southern regions and that the missiles will be deployed "in the right place".
US officials have declined to say how many F-16s would be taking part in the joint exercise or how many might stay on afterwards.
The United States backed a similar move earlier this year in Turkey, with the NATO alliance deploying Patriot missile batteries along Turkey's volatile border with Syria.
During Eager Lion, troops from Britain, Bahrain, Canada, the Czech Republic, Egypt, France, Iraq, Italy, Lebanon, Pakistan, Poland, Qatar, Turkey, the United Arab Emirates, Saudi Arabia and Yemen will stage battlefield, logistics and humanitarian exercises.
The Pentagon had already sent about 200 troops to Jordan to help it prepare for possible military action in Syria, including scenarios to secure the regime's chemical weapons stockpiles.
Jordan is a major beneficiary of US military and economic aid, with Washington granting $2.4 billion (1.85 billion euros) over the past five years, according to official figures.
The war games are being staged with Jordan currently hosting around 500,000 refugees who have fled the civil war in Syria.