By Luke Baker
BRUSSELS (Reuters) - The European Union imposed tighter sanctions on Iran over its disputed nuclear programme on Monday, approving measures to block oil and gas investment and curtail Tehran's refining and natural gas capability.
The restrictions go well beyond sanctions imposed by the United Nations last month and mirror steps taken by the United States this month to apply extra pressure on Tehran to return to negotiations over its uranium enrichment programme.
The measures include widespread limits on dealings with Iranian banks and insurance companies and were accompanied by a call from EU foreign ministers for Iran to resume talks over its enrichment work, which Western powers see as a covert quest for nuclear weapons. Iran says it is for peaceful purposes only.
Diplomats conceded that the sanctions' impact will depend on steps to enforce them fully, a problem in the past.
A spokesman for the Iranian foreign ministry dismissed the EU's new restrictions, saying they would not affect Iran.
"Sanctions will only further complicate the conditions and they will have no impact," Ramin Mehmanparast was quoted as saying by the official news agency IRNA.
"One should think about the necessity of cooperation by all countries in resolving the global crisis."
Britain, which with France and Germany has been the heart of the push for extra Iran sanctions, welcomed the EU's move.
"The message to the Iranian Government could not be clearer: the longer it refuses to talk ... about its nuclear programme, the greater the pressure and isolation Iran will bring upon itself," Foreign Secretary William Hague said.
"But Iran does have a choice: Britain and the international community stand ready to engage, and still believe that the way forward on this issue is multilateral negotiation."
The extra sanctions, which also limit dealings with Iran's state shipping company and with air cargo flights, will not legally come into force until they are published in the European Union's official journal on Tuesday, diplomats said.
Perhaps the hardest-hitting element of the sanctions is the move to prohibit new investment in and technical assistance to Iran's refining, liquefaction and liquefied natural gas sectors which are a mainstay of Iran's energy-based economy.
There is a broad clampdown on the "supply, sale or transfer of items, materials, equipment, goods and technology" that could have "dual-use" -- civilian or military -- purposes, including software, and curbs on financial transfers and bond sales or purchases.
PRESSURE AND DIPLOMACY ALIKE
The broadened sanctions are intended to apply financial heat on Iran, which is the world's fifth largest crude oil exporter but has little refining capability and has to import around 40 percent of its gasoline needs for domestic consumption.
Traders said this month Iran was depending more on friendly countries for fuel supplies to sidestep sanctions intended to hinder its fuel imports, and was buying about half of its July gasoline imports from Turkey and the rest from Chinese sellers.
Only three cargoes of gasoline have so far reached Iran this month, however, according to shipping documents seen by Reuters, a sign that sanctions are biting. Because Iran subsidises fuel for consumers, pump prices will not be affected.
While China, Turkey, Malaysia and others may now step in to furnish Iran with goods it will no longer be able to get from the European Union, analysts said the EU sanctions were well-enough designed to ensure they would be effective.
"Most of the sectors that have been targeted in the EU sanctions are ones over which Europeans have a substantial leverage," Mark Fitzpatrick, an Iran specialist at the International Institute for Strategic Studies, told Reuters.
"Not so many other countries can provide the kind of financial services that will be cut off. Few other countries supply technology for liquefied natural gas, nobody else does re-insurance ... The European Union has very wisely found areas over which it has real leverage and cannot be supplanted."
As part of its "dual-track" approach that twins sanctions and diplomacy, the EU is also hoping that Iran will agree to resume negotiations last carried out in October 2009.
The EU foreign affairs chief, Catherine Ashton, and Iran's chief nuclear negotiator, Saeed Jalili, have exchanged letters in the last few weeks and it looks possible that they will meet for talks as early as September, diplomats say.
Iran experts caution that any resumption of talks -- the first negotiations with the West since October 2009 -- are unlikely to produce quick results, instead beginning a lengthy process of Iran manoeuvring to get sanctions lifted and the West seeking a moratorium on its uranium enrichment.
Iran says it has an inalienable, sovereign right to nuclear energy for civilian purposes and this will not be negotiable.
(Additional reporting by David Brunnstrom and Justyna Pawlak in Brussels, Amena Bakr in Dubai and Luke Pachymuthu in Singapore; Editing by Mark Heinrich)