GENEVA - Iran's youth will witness the demise of Israel and American civilization, Iran's Supreme Leader Ayatollah Ali Khamenei said on Wednesday in comments published on his official website.

"You young people should be assured that you will witness the demise of the enemies of humanity, meaning the degenerate American civilization, and the demise of Israel," Khamenei said in a meeting with students.

He gave no further details.

Tensions have spiked between Iran and the United States after Washington sent more military forces to the Middle East, including an aircraft carrier, B-52 bombers and Patriot missiles, in a show of force against what U.S. officials say are Iranian threats to its troops and interests in the region.

Khamenei said last week that there would be no war with the United States.