RIYADH (FNA) –Saudi Arabia’s King Abdullah Bin Abdulaziz warned that the threat of terrorism will reach Europe and America if the world does not unite to confront it.

The king made the statement during a reception of foreign ambassadors to the kingdom in the coastal city of Jeddah on Friday, Al Arabiya News Channel reported.

Britain on Friday raised the terror threat level to severe, the second-highest level.

The decision was related to developments in Iraq and Syria.

"What we are facing in Iraq now with ISIL is a greater threat to our security than we have seen before,” Prime Minister David Cameron said.

Intelligence and security services now believe around 500 Britons have gone to fight in Syria and potentially Iraq,

Some of the plots are likely to involve fighters who have traveled from Britain and Europe to take part in fighting in the Middle East, Associated Press reported.

The White House said Friday it has no plans to raise terror alert levels in the United States, despite Britain’s decision to raise its threat level to "severe,” according to AFP.

"I don’t anticipate at this point there is a plan to change that level,” White House Spokesman Josh Earnest said, when asked whether Washington anticipated issuing a similar warning to Americans over a perceived threat from operatives of ISIL.

The Obama administration dispensed with its previous color coded threat alert level system for terrorist threats introduced after the September 11 attacks in 2001, reasoning it rarely changed and was often unspecific.

Currently, terror threat alerts are issued by the Department of Homeland Security on a case-by-case basis, but there are no current alerts.