Yukiya Amano, who led the UN nuclear watchdog to take a tougher approach to Iran, secured a second four-year term as head of the International Atomic Energy Agency on Wednesday.

The veteran Japanese diplomat was approved by consensus by the IAEA's 35-nation governing board as Iran came under increasing pressure from Western countries which suspect it of developing nuclear weapons technology.

Western diplomats are generally happy with Amano - who only narrowly won the job in 2009 when he succeeded Egyptian Mohamed ElBaradei whom they criticised for taking a softer line on Tehran. There were no rival candidates this time.

Iran, which denies it is seeking nuclear weapons and accuses the West of using its scientific progress as an excuse to bully it with sanctions, is less happy with Amano.

Tehran has rejected the IAEA's request to visit a military facility where the agency suspects explosives tests relevant for nuclear weapons development took place, possibly a decade ago.

"There have been some ups and downs," said Ali Asghar Soltanieh, Iran's envoy to the IAEA, when asked about Amano's performance. "We really expect and hope that he will change the course of action."

Diplomats say Amano's IAEA has at times also had uneasy relations with Russia.

Russia, and to a lesser extent China, made clear their displeasure with the agency's decision in late 2011 to issue a report giving a wealth of information pointing to activities in Iran relevant for nuclear weapons development.

BIG CHALLENGES

Western powers seized on the report to tighten the sanctions pressure on Iran, a major oil producer. Beijing and Moscow have criticised unilateral punitive steps on Tehran.

Soltanieh said Amano's reports on Iran's nuclear programme "provoke" IAEA member states. "We cannot accept that we will continue to have political pressure and tension on the board of governors," he said. Iran is not a member of the IAEA board.

Amano, 65, said he faced "many and huge challenges" in his work and that the aim was to help resolve the Iran nuclear issue through diplomatic means.

"For that I need cooperation from Iran," he told reporters after the board decided on his re-appointment, which needs to be confirmed by an annual meeting of all 159 IAEA member states in September.

Under Amano, the IAEA was criticised in 2011 for a perceived slow initial response to Japan's Fukushima nuclear disaster, but later led international efforts to agree an action plan to improve global reactor safety.

In 2009, supported largely by industrialised nations, Amano defeated South Africa's Abdul Samad Minty in a sixth round of balloting after five inconclusive votes.

The United States and Israel were deeply suspicious of ElBaradei, who ran the Vienna-based IAEA from 1997 to 2009, and what they saw as his attempts to undermine efforts to ratchet up the pressure on Iran over its nuclear programme.

In 2010, Britain's Guardian newspaper cited US diplomatic cables as saying that Amano suggested before he took office the previous year that he was "solidly in the US court" on key issues including Iran. - Reuters