Iran on Sunday hit out at talk of more EU sanctions being applied against it as "irresponsible," singling out Britain for raising the prospect it claimed went against UN nuclear watchdog regulations.
Foreign ministry spokesman Ramin Mehmanparast issued a statement relayed by state broadcaster IRIB calling Western sanctions "ineffective" and "obsolete."
He was reacting to comments made by EU foreign ministers, meeting in Cyprus on Saturday, who said a "growing consensus" was forming to impose new punitive measures on Iran to pressure it further to make concessions on its disputed nuclear programme.
British Foreign Secretary William Hague said after the meeting that existing EU sanctions were having "a serious impact" but it was "necessary to increase the pressure on Iran, to intensify sanctions."
Britain would urge EU governments to agree a new round of sanctions -- targeting the energy sector and trade -- at the next meeting of EU foreign ministers in mid-October, a diplomatic source at the meeting told AFP.
Hague's German and French counterparts echoed that position, underlining EU frustration that talks this year between Iran and the so-called P5+1 group -- Britain, France, Germany, the United States, Russia and China -- had gone nowhere.
Mehmanparast homed in on Britain's position, saying: "The recent remarks by the British foreign secretary calling for increasing sanctions against Iran are irresponsible."
He said they "violate" International Atomic Energy Agency regulations.
He also claimed Hague's remarks sought to undermine Iran's recent hosting of a summit on non-aligned states that supported the Islamic republic's nuclear energy programme as long as it complied with IAEA oversight.
UN chief Ban Ki-moon, attending that summit, had urged Iran to abide by IAEA demands for broader inspections and six UN resolutions it has so far ignored demanding it suspend uranium enrichment.
The P5+1 harbours suspicions that Iran's nuclear activities include a push to develop an atomic weapon breakout capability.
Tensions over the issue have greatly risen in recent months, since the Iran/P5+1 negotiations effectively stalled in June.
Israel -- the Middle East's sole if undeclared nuclear weapons power -- has threatened to possibly launch imminent air strikes on Iran's nuclear facilities.
The United States, which has repeated it could also take military action against Iran as a last resort, is arguing with Israel that diplomacy has not yet run its course.
Iran insists its nuclear programme is exclusively peaceful and points to edicts from its supreme leader, Ayatollah Ali Khamenei, describing nuclear weapons as a "great sin."
However, the IAEA in its latest report stressed Iran has repeatedly rebuffed its requests to be given access to a military base suspected to have carried out experiments using conventional explosive to test possible nuclear warhead designs.
It also said Iran had installed more than 1,000 new uranium enrichment centrifuges in a bomb-proof nuclear bunker in Fordo, near the holy city of Qom, though had not yet switched them on.
EU and US sanctions imposed in July have severely crimped Iran's all-important oil exports.
According to OPEC, Iran's oil production has plummeted to its lowest level in more than two decades, while the International Energy Agency says its oil exports have more than halved this year.
Iranian President Mahmoud Ahmadinejad admitted on Tuesday that his country had "some problems in selling oil" because of the sanctions, but he said "we are trying to manage it."