LONDON (AP) _ Britain's foreign policy chief said Friday that Iran continues to pose the most serious threat to the world, warning that Tehran's suspected pursuit of nuclear weapons risks an arms race across the Middle East.

David Miliband said in a speech that the standoff over Iran's nuclear program -- which Tehran insists is aimed at developing a civilian energy program but which Western leaders say is an effort to make nuclear weapons -- must be quickly resolved.

"In the next year, the most pressing threat to global order ... comes from the actions of Iran," said Miliband, Britain's foreign secretary. "Its refusal to address the international community's concerns about its pursuit of nuclear enrichment threatens to spark a nuclear arms race throughout the Middle East."

Miliband said that if Iran persists, Egypt, Saudi Arabia, Turkey and others could be forced to consider whether they also need nuclear weapons to defend their interests. Israel is widely considered to have nuclear arms but has a "no tell" policy on the issue.