Seven Jordanian militants pleaded not guilty on Wednesday to charges of having plotted a prison break to free an Al Qaeda member convicted of planning chemical attacks on the kingdom.

The alleged beneficiary of the plan, Azmi al-Jayousi, was sentenced to death in February along with several other militants for a 2004 plan to launch chemical attacks on Jordan.

Authorities said the militants planned to unleash toxic chemical clouds against the Intelligence offices, the U.S. Embassy in Amman and the prime minister's office.

Al-Jayousi was described by the indictment as the evasion plot's mastermind. He was among the nine defendants tried on Wednesday, including two in absentia.

Authorities said they uncovered the evasion attempt in January when they searched the car of accomplices visiting al-Jayousi in prison and discovered several automatic riffles and ammunition.

The hearing has been adjourned until July 13.

In a separate trial, a witness for the prosecution in the case of militants charged with firing rockets at two U.S. warships docked in the Gulf of Aqaba said they had used Chinese-made rockets in the attack.

On Aug. 19 last year, two rockets were fired from a warehouse on the outskirts of Jordan's sole Red Sea port and narrowly missed the USS Ashland docked in the bay, killing a Jordanian soldier who was guarding the port. The other rocket landed across the border in Israel, but did not explode and lightly wounded an Israeli taxi driver.

Al Qaeda in Iraq, the group led by Jordanian-born Abu Musab Al-Zarqawi who was killed in a U.S. strike in Iraq last month, claimed responsibility for the incident.

The defendants allegedly smuggled the rockets into Jordan from Iraq.

The indictment said the 12 defendants also planned to attack the U.S. and Israeli embassies in Amman, and they were providing funds to insurgents in Iraq.

Six defendants are on trial while six others are being tried in absentia.

The hearing was adjourned until July 12.