China's arms control chief has urged the US and Russia - the world's largest nuclear powers - to reduce their arsenals drastically as the two countries began a new round of disarmament talks in Moscow yesterday.

"A world without nuclear weapons is a fine vision. To realize it, the international community expects the two powers to take concrete action," Cheng Jingye, director-general of the arms control and disarmament department of the Foreign Ministry, told China Daily.

Cheng said that Moscow and Washington appear willing to strike a new deal this year to replace their Strategic Arms Reduction Treaty, which will expire on Dec 5.

He said it is vital for Russia and the US to agree on "verifiable, irreversible nuclear disarmament", saying the international community hopes to see the two powers take tangible steps to eventually destroy their nuclear arsenals.

A 2002 disarmament agreement between the two countries, known as the Moscow Treaty, to cut their nuclear arsenals to around 2,000 warheads from 6,000 did not require the reduction to be verifiable or irreversible.

Cheng was talking to China Daily after returning from the United Nations headquarters for a preparatory committee session to review the 39-year-old Nuclear Non-Proliferation Treaty (NPT) in May next year.

For the first time in 15 years, the preparatory session succeeded in drawing up an agenda for an NPT review acceptable to both the nuclear powers and non-nuclear states. Though the meeting failed to agree on recommendations for the review conference, held every five years, delegates said the talks had broken the deadlock.

Cheng said he is optimistic about the prospects for the review conference, which failed to yield any result in 2005, but some issues such as the controversy surrounding the nuclear capability of certain countries could still cause problems.

"The Chinese government opposes any form of nuclear proliferation, and rejects using non-proliferation as an excuse for obstructing peaceful application of nuclear energy," Cheng said.

He also said that Beijing's stance on non-proliferation has been consistent since it first tested a nuclear weapon in 1964, and the government has been active in nuclear disarmament.

The Chinese army has not revealed the extent of its warhead stockpile but military observers, including the Stockholm International Peace Research Institute and UK-based Jane's Defence, estimate the number at between 100 and 1,000. "The proposals by US President Barack Obama are consistent with China's long-term principles for complete prohibition and total destruction of nuclear arms," Cheng said.

Assistant Foreign Minister Liu Jieyi told a forum in Beijing yesterday that China is keen to make joint efforts with the international community to realize a nuclear-free world.

Cheng also said the government supports the early entry-into-force of the Comprehensive Nuclear Test Ban Treaty and will also back an early agreement on a ban on the production of fissile material used in nuclear weapons.

China is the only country among the five nuclear powers under the NPT which has a declared "no first use" policy for nuclear weapons, and promises not to use nuclear weapons against any non-nuclear country or nuclear-weapon-free zone.

Questions:

1. In which city did a new round of nuclear disarmament talks begin yesterday?

2. When will the strategic arms reduction treaty expire?

3. What was the estimated number of nuclear weapons both the US and Russia each had in 2002?

4. What is the only country among the five nuclear powers that has declared a no first use policy?

Answers:

1. Moscow.

2. December 5.

3. 6000 warheads .

4. China.