LUCCA, Italy (AP) — Foreign ministers from the Group of Seven industrialized nations met Monday to forge a response to the deadly chemical attack in Syria, and British Foreign Secretary Boris Johnson said they would consider imposing sanctions against Russian backers of President Bashar Assad.

G-7 diplomats gathering in Lucca, Italy, hope to use outrage over the attack and wide international support for the United States’ retaliatory missile strikes to push Russia to abandon Assad and join a new peace effort for Syria.

Speaking after meeting with U.S. Secretary of State Rex Tillerson, Johnson said ministers “will be discussing the possibility of further sanctions, certainly, on some of the Syrian military figures and indeed on some of the Russian military figures.”

He said Russia had a choice: to continue backing the “toxic” Assad regime, “or to work with the rest of the world to find a solution for Syria, a political solution.”

Last week’s nerve gas attack in the rebel-held town of Khan Sheikhoun, which killed more than 80 people, stirred President Donald Trump — who was previously cool to the idea of U.S. intervention — to strike for the first time at Assad’s forces. U.S. warships fired 59 cruise missiles at the Syrian air base from which the U.S. believes the attack was launched.

Tillerson said Monday at the site of a World War II-era Nazi massacre in central Italy that the United States is rededicating itself to hold to account “any and all” who commit crimes against innocent people.

With the group of wealthy nations working to see if it can strike a common front on Syria, Tillerson accompanied Italian Foreign Minister Angelino Alfano to Santa’Anna di Stazzema, where 560 civilians, including some 130 children, were killed in 1944.

Alfano said the site of past Nazi atrocities was a reminder that “peace is not a given. … That is why we are here to work all together for peace and liberty.”

The meeting in the Tuscan walled city of Lucca brings together the foreign ministers of France, Germany, Britain, Japan and Canada — as well as the U.S. and current G-7 president Italy.

Ahead of the full meeting, Tillerson held bilateral talks with G-7 counterparts who included Japanese Foreign Minister Fumio Kishida, French Foreign Minister Jean-Marc Ayrault and Britain’s Johnson.

Tillerson also spoke by phone with Turkish Foreign Minister Mevlut Cavusoglu, whose government insists Assad should play no role in Syria’s future.

Over the weekend, Alfano said that Europe’s broad support for the U.S. military strikes had contributed to a “renewed harmony” between the United States and its partners as the G-7 foreign ministers prepared to meet for the first time since Donald Trump took office in January.

“We need to remember that not 10 years ago, but 100 or 120 days ago, the concern in Europe was that the United States and the EU were moving apart,” Alfano told Sky TG24 Sunday. “I welcome this renewed harmony.”

After meeting Tillerson, Japan’s Kishida said “Japan supports the U.S. commitment in trying to take responsibility to prevent spread and use of chemical weapons and we confirmed Japan and the U.S. will continue to work together (in that effort).”