LUCCA, Italy (AP) — Foreign ministers from the Group of Seven industrialized nations are expected to call Tuesday for a new international push to end the war in Syria, but are divided on whether to threaten new sanctions or other tough measures to pressure Russia over its support of President Bashar Assad.

The G-7 blames Assad's military for a deadly chemical attack last week.

British Foreign Secretary Boris Johnson has said the G-7 is considering new sanctions on Russian military figures to press Moscow to end military support for the "toxic" Assad government. U.S. officials in Washington have also raised that prospect.

Others want a more conciliatory approach to Moscow. German Foreign Minister Sigmar Gabriel said Russia, and Assad ally Iran, must be involved in any peace process to end Syria's six-year civil war.

Gabriel said the United States had "sent a clear signal to the Assad regime" by launching cruise missiles at a Syrian air base, but said other nations should "reach out to Russia" rather than seek a military escalation.

"Not everyone may like it, but without Moscow and without Tehran there will be no solution for Syria," he said.

Japanese foreign ministry spokesman Masato Ohtaka said that "in terms of dialogue and other political engagement I think a lot of countries think that Russia can play a key role."

The G-7 wants to deliver a united message to Russia through U.S. Secretary of State Rex Tillerson, who heads to Moscow after Tuesday's meeting in Lucca, Italy.

The other G-7 members — Germany, France, Britain, Canada, Japan and current president Italy — are also trying to grasp what the U.S. administration's foreign policy is, amid conflicting signals from Washington.

British Prime Minister Theresa May's office said she and U.S. President Donald Trump spoke by phone Monday and agreed there is a "window of opportunity" to persuade Russia that its support for Assad is "no longer in its strategic interest."

Tillerson's trip comes after an American official said the U.S. has drawn a preliminary conclusion that Russia knew in advance of the chemical attack — an allegation that heightens already acute tensions between Washington and Moscow.

Until Trump ordered U.S. missile strikes on a Syrian air base in response to the nerve gas attack that killed more than 80, the president had focused on defeating the Islamic State group and had shown no appetite for challenging Assad — and, by extension, his Russian supporter President Vladimir Putin.

Even since the missile strikes, signals have been mixed.

After the April 4 chemical attack, Trump said his attitude toward Assad "has changed very much" and Tillerson said "steps are underway" to organize a coalition to remove him from power. But Tillerson also said that the top U.S. priority in the region remains the defeat of Islamic State militants.

On Monday Tillerson raised fresh expectations for aggressive U.S. action — and not only in Syria — as he visited the site of a World War II Nazi massacre in central Italy, saying the U.S. would hold to account "all who commit crimes against the innocents anywhere in the world."

Though such comments hint at a more activist U.S. foreign policy focused on preventing humanitarian atrocities, Trump has consistently suggested he prefers the opposite approach. His new administration has generally downplayed human rights concerns while promoting an "America First" strategy de-emphasizing the concerns of foreign nations.

Uncertainty about objectives persisted as Tillerson met Tuesday on the sidelines of the Lucca meeting with diplomats from "like-minded" countries on Syria, including Turkey, Jordan, Saudi Arabia and the United Arab Emirates as well as G-7 members.

The U.S. hopes the regional countries can help ensure security and stability in Syria after the Islamic State group is defeated.

The G-7 meeting is taking place amid an ongoing terror threat that was underscored by the Palm Sunday bombing of Coptic churches in Egypt claimed by the Islamic State group, and another truck attack on European soil, this time in Stockholm, on Friday.

It also comes as the United States is sending a Navy carrier strike group toward the Korean Peninsula in a show of strength following North Korea's persistent ballistic missile tests.

Ohtaka, the Japanese foreign ministry spokesman, said Japan hoped the G-7 diplomats would take a firm stand against Pyongyang's "totally unacceptable" missile tests.

"The situation does not seems to be getting better at all and I think the international community, including Japan and the U.S., would need to show its determination to resolve the situation and to make a strong commitment to actually get the international community on board on this one as well," he said.

Colleen Barry in Milan and Geir Moulson in Berlin contributed to this report.