The foreign ministers of the Group of Seven industrialized nations were gathered in Toronto on Sunday seeking a common front against what they see as provocation from Vladimir Putin's Russia.
The envoys will also be keen to glean clues from their US colleague about whether President Donald Trump plans to tear up the Iran nuclear deal and how he will handle a planned summit with North Korea's Kim Jong Un.
The envoys from the world's most powerful democracies are meeting to plan for June's G7 summit of rich-world leaders in Charlevoix, Quebec -- but Russia will never be far from their minds.
Acting US Secretary of State John Sullivan's first bilateral meeting in Toronto late Saturday was with Ukraine's Foreign Minister Pavlo Klimkin. Neither official spoke to reporters as the talks began.
From Klimkin, Sullivan would expect to hear about Kiev's struggles to regain control over eastern Ukraine's Donbas region, in the hands of Russian-backed rebels, and Crimea, which Moscow has annexed.
On Sunday, Canada's Foreign Minister Chrystia Freeland will host all of her G7 colleagues plus the European Union's representative at a working lunch to discuss the crisis in Russia and Ukraine.
- Deadly nerve agent -
G7 capitals are also worried about Russia's role in supporting Syrian leader Bashar al-Assad's regime in his country's brutal civil war and alleged attempt to kill a defector with a nerve agent on Russian soil.
On Monday, the foreign ministers issued a joint statement urging the Kremlin to address "all questions related to the incident" and to make a "full and complete disclosure of its previously undeclared Novichok program."
Novichok is a group of deadly chemical compounds reportedly developed by the Soviet government in the 1970s and 80s and which Britain suspects was used to poison former Russian spy Sergei Skripal in Salisbury in March.
After their lunch, the ministers will also hold a meeting on North Korea and nuclear non-proliferation.
Last month, in one of the most surprising twists in world affair for decades, Trump accepted an invitation from Pyongyang's eccentric autocrat Kim to a summit to discuss his nuclear disarmament.
- Tougher nuclear controls -
The G7 members, including frontline state Japan, support efforts to convince Kim to end his efforts to develop a strategic nuclear missile arsenal, but are also keen to hear more from the US side.
Kim is sure to have demands of the West, and the allies are keen to ensure that Trump does not give too much away to secure a historic deal.
The North Korea meeting will be followed by one of the so-called "Quad" -- the United States plus France, Britain and Germany, the Western partners who, with Russia and China, signed the 2015 Iran nuclear deal.
Trump has threatened to tear the agreement up unless European capitals agree to supplement it with tougher controls on Iran's missile program and future ability to return to nuclear fuel enrichment.
But his partners continue to believe the core agreement represents to best way to prevent Tehran from seeking the atomic bomb, and will not miss a chance to lobby Sullivan to convince Trump to reverse course.
The Toronto talks may be Sullivan's last high-level international confab as acting secretary. CIA director Mike Pompeo has been nominated to replace him as Washington's top diplomat and may be confirmed this week.