It was the European Union's "big three" -- Britain, France and Germany -- who on Friday pushed through a tough resolution at the International Atomic Energy Agency (IAEA) that blasted Iran for failing to honour its pledge to come clean.
The EU heavyweights had brokered a deal in October for Iran to cooperate with the UN watchdog, but in a sign of growing impatience have now edged closer to the position of the United States -- which stands by its accusation that Iran's clerical rulers are seeking nuclear weapons and not just electricity.
The resolution repeats a call by IAEA director general Mohamed ElBaradei "that it is essential for the integrity and credibility of the inspection process to bring these issues to a close within the next few months."
And it "deplores... that Iran's cooperation has not been as full, timely and proactive as it should have been."
Iran has responded by toughening its stance, raising the threat of resuming uranium enrichment and accusing the Europeans of betrayal.
On the human rights issue, relations are not going well either.
The Irish EU presidency Sunday issued a blistering statement on the regime's record, saying the 25-member bloc remained "gravely concerned" at the persistence of widespread abuses despite several rounds of lengthy talks.
"The European Union continues to be gravely concerned at the continued and numerous violations of human rights in Iran," said a statement released by the Irish embassy here.
"These include unequal rights for women; the use of torture in prisons and other places of detention, and a culture of impunity for perpetrators."
It also pointed to "the lack of an independent judiciary, the use of the death penalty, as well as reports of the continued use of amputations and other cruel punishments; a continuing campaign against journalists and others who seek to exercise their freedom of opinion and expression, a flawed electoral process which impedes the democratic choice of the Iranian people, and discrimination on religious grounds."
An EU delegation and Iranian officials had met here on Monday and Tuesday, the fourth time the two sides have sat down since December 2002.
The statement said the EU delegation had "raised the cases of 40 prisoners of conscience at present in detention in Iran, who should be released immediately and definitively."
It did not say how the Iranians responded to the demand, but the tone of the statement appeared to back up comments from diplomats that the latest talks had netted "no concrete results". Last week, a senior official in the hardline judiciary even denied the presence of any political prisoners in Iranian jails.
Diplomats also said the meeting here -- the first since the effective ouster of reformists from parliament by religious conservatives -- also failed to fix a date for a fifth round of talks.
"We started off with critical dialogue; then we moved onto constructive dialogue; and now we seem to be in a phase of monologue," was the wry spin on EU policy towards Iran given by one senior Tehran-based European diplomat.
As well as engaging Iran on the nuclear issue and human rights, the EU is also looking for progress in Iran's record on terrorism and a change in its stance on the Israeli-Palestinian conflict.
Tehran's official position is that Israel should be destroyed. On terrorism, various arms of Iran's security apparatus are suspected of harbouring al-Qaeda members, promoting anti-coalition violence in Iraq and financing attacks by Palestinian militants.
The European Union has made progress on these matters a condition for signing a proposed trade and cooperation agreement.
The tone among diplomats now is that for Iran such a deal is as elusive as ever, even if they are -- for the time being -- stopping short of suggesting the dialogue is about to grind to a halt.