US Secretary of State John Kerry was bound for Europe on Monday ahead of talks between international powers and Iran on that country’s nuclear program.

US Secretary of State John Kerry was bound for Europe on Monday ahead of talks between international powers and Iran on that country's  nuclear program.

Shortly before departing for London, where he will consult with European counterparts Tuesday, Kerry acknowledged the vital nature of the upcoming talks with Tehran ahead of a November 24 deadline to reach agreement on its nuclear drive.

"We are obviously entering a key period with the negotiations regarding Iran's nuclear program, and I will go to Vienna at the appropriate moment," Kerry said at a Washington forum, referring to the negotiations due later this week in the Austrian capital.