Germany's foreign minister is pushing for an agreement in negotiations over Iran's nuclear program by a Nov. 24 deadline, saying it is a "make-or-break moment" and another opportunity is unlikely to arise soon.

Germany, the U.S. and four other powers have spent years addressing concerns over Iran's nuclear ambitions. However, two days of tough talks ending Monday failed to make major headway toward a final deal.

Foreign Minister Frank-Walter Steinmeier said Tuesday that flexibility and "strength of leadership" on all sides are needed to seal a compromise.

Steinmeier says he is "convinced that the situation won't come around again so soon." He says he fears that simply extending negotiations "won't bring the solution — not in the next two years."