US Secretary of State Colin Powell and Jordan's King Abd Allah will be among around 1000 participants at the three- day conference that will focus on regional economic reform, transition in Iraq and the Palestinian-Israeli conflict. 

Jordanian forces tightened security in the capital Amman and on the road to the Dead Sea, witnesses said on Friday. Heavily armed soldiers in Humvees and other armoured cars manned checkpoints as troops lined the airport road. 

Naval boats also patrolled the coast of the Jordanian side of the Dead Sea. 

'Massive attack'

Jordan said last month it had thwarted a "massive attack" against its intelligence headquarters in Amman by a group linked to Usama bin Ladin's al-Qaida network. 

Jordanian officials have regularly reported foiling plans to attack Israeli and US interests in the kingdom. 

Top financial officials, ministers and about 500 business people would attend the meeting, held in Jordan for the second successive year.