The UN Security Council has voted in favour of fresh sanctions against Iran over its nuclear programme.

The council voted 12 to two, with one abstention, in favour of a fourth round of sanctions, including tighter finance curbs and an expanded arms embargo.

US President Barack Obama said the sanctions were an unmistakable message on stopping the spread of nuclear arms.

Iran's President Mahmoud Ahmadinejad said the sanctions should be thrown in the dustbin like a "used handkerchief".

The US and its allies fear Iran is secretly trying to build a nuclear bomb, but Tehran insists its programme is aimed solely at peaceful energy use.

Heavy weapons

The Security Council resolution was opposed by Turkey and Brazil. They had earlier brokered a deal with Iran on uranium enrichment. Lebanon abstained.

ANALYSIS The sanctions are tough but fall short of what Western nations wanted because of pressure from Iran's allies Russia and China. However, they do open the way for stronger measures by the US and European states. But council members Turkey and Brazil said any sanctions at this moment were counter-productive and insisted Iran had made concessions in a recent agreement they brokered. The two "no" votes were the strongest opposition yet in four rounds of sanctions, weakening international unity the Americans have tried to build to isolate Iran. Last resort or lost opportunity?

The new sanctions were passed after being watered down during negotiations with Russia and China on Tuesday.

There are no crippling economic sanctions and there is no oil embargo.

Those passed include prohibiting Iran from buying heavy weapons such as attack helicopters and missiles.

They also toughen rules on financial transactions with Iranian banks and increase the number of Iranian individuals and companies that are targeted with asset freezes and travel bans.

There is also a new framework of cargo inspections to detect and stop Iran's acquisition of illicit materials.

Mr Obama accused Iran's leaders of "hiding behind outlandish rhetoric".

But he said the sanctions did "not close the door on diplomacy" and he urged Iran to "choose a different and better path".

Mr Ahmadinejad was quoted by Iran's Isna news agency as saying: "I gave one of the [world powers] a message that the resolutions you issue are like a used handkerchief which should be thrown in the dustbin. They are not capable of hurting Iranians."

UK Foreign Secretary William Hague said the decision sent a "strong statement of international resolve", increasing the pressure on Iran to meet its obligations.

China's UN ambassador Zhang Yesui said the sanctions were trying to prevent nuclear proliferation and would not hurt "the normal life of the Iranian people".

However, both Turkey and Brazil spoke out in opposition, saying the deal they brokered with Iran had not been given time.

Brazilian ambassador to the UN Maria Luiza Ribeiro Viotti said: "We do not see sanctions as an effective instrument in this case. They will most probably lead to the suffering of the people of Iran and will play into the hands of people on all sides who do not want dialogue to prevail."

Turkey's envoy Ertugrul Apakan said the Turkey-Brazil deal had created "a new reality" on Iran's nuclear programme and Turkey was "deeply concerned" that sanctions would have a negative impact.

HOW THE COUNCIL VOTED FOR Permanent (with power of veto): China; France; Russia; UK; US Non-permanent (term ends 2010): Austria; Bosnia-Herzegovina; Gabon; Japan; Mexico; Nigeria; Uganda AGAINST Non-permanent: Brazil and Turkey. Had both brokered a deal with Iran in which Tehran would send low-enriched uranium to Turkey in return for reactor fuel ABSTAINED Non permanent: Lebanon. Had voiced opposition to the sanctions. Iran-backed Hezbollah is part of the government

Prof Abbas Edalat, the founder of the Campaign against Sanctions and Military Intervention in Iran, told BBC Radio 4's PM programme that the sanctions would make "everything worse".

He said: "What the US has done has proved conclusively beyond any doubt that it is not interested in negotiations with Iran... There has been massive hypocrisy here."

The BBC News website's world affairs correspondent, Paul Reynolds, says this new round of sanctions is unlikely to have any more effect on Iranian policy than the first three.

Iran's vital economic interests have not been targeted, he says, and Tehran has in any case developed systems of evasion.

The deal Iran had earlier agreed with Turkey and Brazil would see Tehran deposit 1,200kg of low-enriched uranium with Turkey in return for reactor fuel.

But the deal has not been accepted by world powers and on Wednesday, the US, Russia and France outlined their concerns in letters to the IAEA.

The letters were not made public, but US envoy to the IAEA Glyn Davies said the deal "would still leave Iran with substantial stocks [of low-enriched uranium], decreasing the confidence-building value of the original proposal".

Three earlier rounds of UN sanctions blocked trade of "sensitive nuclear material", froze the financial assets of those involved in Iran's nuclear activities, banned all of Iran's arms exports and encouraged scrutiny of the dealings of Iranian banks.