The head of the U.N. nuclear agency appears on track to stay in office for a second term, with his organization saying no other candidate has stepped forward to challenge him.

The lack of competition means that International Atomic Energy Agency chief Yukiya Amano will likely be approved by the IAEA's board of governors to run the agency for four more years.

IAEA spokeswoman Gill Tudor said Monday that no challenger to Amano, of Japan, had surfaced by the Dec. 31 deadline. Approval of his extension by another four years is expected at the 35-nation board's March meeting.

But Amano may be criticized by some countries at that session for perceived anti-Iran bias in the IAEA's probe of suspicions that Tehran seeks nuclear arms - a charge Iran denies.