Canada's foreign minister on Thursday vowed to push Iran for answers about the mistaken downing of a passenger plane amid high tensions after the US killed one of Tehran's top commanders.
The plane was hit and all 176 people on board were killed just hours after Iran fired strikes against US troops stationed in Iraq in retaliation for a drone attack that killed its most prominent general, Qasem Soleimani.
"In the wake of such a horrific tragedy there are many questions," Francois-Philippe Champagne said at a meeting in London.
"Families want answers, the international community wants answers, the world is waiting for answers and we will not rest until we get them."
Champagne was speaking after talks with counterparts from countries whose nationals were among those killed when the plane was hit after taking off from Tehran last week.
Fifty-seven of the victims on board the Kiev-bound Ukraine International Airlines flight were Canadian.
Iran's initial denial of claims, based on US intelligence, that the Boeing 737 was hit by a missile sparked days of protests and international calls for a full and transparent investigation.
But the Islamic republic later accepted the jet had been targeted "unintentionally". President Hassan Rouhani called it an "unforgivable mistake".
In a joint statement after Thursday's talks, Canada, Ukraine, Sweden, Afghanistan and Britain issued a five-point plan for cooperation with Iran.
It called for "full and unhindered access" for foreign officials to and within Iran and "a thorough, independent and transparent international investigation".
Iran should "assume full responsibility for the downing of flight PS752 and (recognise) its duties towards the families of the victims and other parties -- including compensation".
In addition, it called for those responsible to be held to account in an independent criminal investigation and trial in line with international standards of due process and human rights.
- 'Grief and anger' -
Champagne told a news conference that families of those who died needed closure and there was a need to prevent similar incidents in the future.
"When you accept full responsibility there are consequences coming from that," he said.
"Today is not the day for blame, today is the day for answers," he added, saying the families had "grief and anger and they want us to stand for them".
The ministers earlier took part in a candle lighting ceremony and a moment's silence at Canada House in London in memory of the victims.
The United States said on Tuesday that it supported the three EU countries that launched a process charging Iran with failing to observe the terms of the 2015 deal curtailing its nuclear programme.
Britain, France and Germany began the dispute process in the wake of Soleimani's death.
German's defence minister Annegret Kramp-Karrenbauer on Thursday confirmed reports that US President Donald Trump threatened the EU3 with a 25-percent tariff on car exports if it continued to back the deal.
British minister Andrew Murrison said the government wanted to keep the deal alive, assessing it was the "best hope" of preventing Iran from acquiring a nuclear weapon.
President Rouhani said earlier on Thursday that his country's "daily enrichment" of uranium was currently "higher" than before the conclusion of the 2015 nuclear deal.
He did not specify whether Iran was now producing a greater quantity of enriched uranium, or whether it was enriching ore with uranium 235 isotopes at a higher level than before the deal.