WEST PALM BEACH, Fla. (AP) — When America’s top diplomat called to offer condolences over the killing of his son in the Israeli airstrikes that hit a World Central Kitchen convoy delivering aid in Gaza, John Flickinger knew what he wanted to say.

The grieving father told Secretary of State Antony Blinken that the killings by Israel in the Hamas-run territory must end, and that the United States needs to use its power and leverage over its closest Mideast ally to make that happen.

Flickinger’s 33-year-old son, Jacob Flickinger, a dual U.S. and Canadian citizen, was among the seven humanitarian workers killed in the April 1 drone strikes.

“If the United States threatened to suspend aid to Israel, maybe my son would be alive today,” John Flickinger told The Associated Press in describing his 30-minute conversation Saturday with Blinken.

More on the Israel-Hamas war Israel is pulling some troops from southern Gaza. Now the plan is to clear Hamas from Rafah Israel says its strike that killed aid workers was a mistake. Rights groups say it was no anomaly Aid worker deaths have appalled Israel’s European allies. Some are considering a halt to arms sales

Flickinger said Blinken did not pledge any new policy actions but said the Biden administration had sent a strong message to Israeli Prime Minister Benjamin Netanyahu that the relationship between the United States and Israel may change if the Israeli Defense Forces do not show more care for the fate of Gaza’s civilians.

“I’m hopeful that this is the last straw, that the United States will suspend aid and will take meaningful action to leverage change in the way Israel is conducting this war,” John Flickinger said.

Flickinger said Blinken also spoke with his son’s partner, Sandy Leclerc, who is left to care for their 1-year-old son, Jasper.

In addition to Jacob Flickinger, three British nationals, an Australian, a Polish national and a Palestinian were killed in the strikes.

John Flickinger described his son as “larger than life,” a “loving son, a devoted dad and new father and a very loving companion to his life partner.”

Jacob Flickinger was remembered as a lover of the outdoors who ran survival training retreats and was involved in mountaineering, rock climbing and other adventure activities. He spent about 11 years serving in the Canadian Armed Forces, including eight months in Afghanistan.

The elder Flickinger said his son knew going to Gaza was risky, but he discussed it with family members and volunteered in hopes of helping Palestinians in Gaza that aide groups say face imminent famine.

“He died doing what he loved, which was serving and helping others,” said Flickinger, whose own nonprofit, Breakthrough Miami, exposes underrepresented students to academic opportunities and prepares them for college.

World Central Kitchen representatives have said they informed the Israeli military of their movements and the presence of their convoy.

Israeli officials have called the drone strikes a mistake, and on Friday the military said it dismissed two officers and reprimanded three others for their roles. The officers mishandled critical information and violated rules of engagement, the military said.

But John Flickinger said that in his view the strike “was a deliberate attempt to intimidate aid workers and to stop the flow of humanitarian aid.”

World Central Kitchen has since ceased food deliveries in Gaza, Flickinger noted, and he said it looks like Israel is “using food as a weapon.”

The Canadian government has been communicating with the family and is offering financial support to move Leclerc and Jasper from Costa Rica, where the family lives, back to Quebec province to be closer to family, Flickinger said.

Flickinger said his son’s remains are in Cairo pending the issuance of a death certificate by Palestinian authorities. Once that happens, the family has made arrangements for them to be transported to Quebec.