Saudi Arabia’s King Abdullah says the threat of terrorism would reach Europe and the US if it is not confronted on an international scale, according to the country's official news agency, the Saudi Press Agency.

During a speech to foreign ambassadors at a reception in his hometown of Jeddah, the Saudi monarch urged them to convey a message to their governments: "Terrorism must be fought with force, reason and speed."

World leaders should hastily respond to the "evil" threat of terrorism before it spreads beyond the borders of the Middle East, he warned. "Terrorists do not know humanity."

His speech addressed the mass killings and public beheadings committed "day and night" across the Middle East, which went "against the teachings of Allah" and ignored the "sanctity of human life."

King Abdullah noted that atrocities did not stop there, with terrorists "even killing themselves."

"I am sure they will arrive in Europe in a month," he said, "and in the US a month after that."

His comments come as US Secretary of State John Kerry warned against the danger of leaving the ISIS threat unchecked.

"There is evidence that these extremists, if left unchecked, will not be satisfied at stopping with Syria and Iraq," he stated in an op-ed piece in the New York Times on Saturday. "They have already demonstrated the ability to seize and hold more territory than any other terrorist organization, in a strategic region that borders Jordan, Lebanon and Turkey and is perilously close to Israel."

Prime Minister Binyamin Netanyahu has also been calling on the international community to unite to topple terrorist groups. Indeed, the ISIS threat has created some common ground between Israel and moderate Arab states like Saudi Arabia, Egypt and Jordan. As the proverb goes: "The enemy of my enemy is my friend."

Please LIKE our Facebook page - it makes us stronger