President Trump’s proposal for an Israeli-Palestinian peace deal is “fairly well advanced,” according to Secretary of State Rex Tillerson.

“It’s been under development for a number of months,” Tillerson told reporters in Amman, Jordan. “I will say it’s fairly well advanced.”

Tillerson is traveling in Jordan as part of a Middle East trip focused on counter-terrorism and the crisis in Syria. He unveiled a $274 million increase in U.S. aid to Jordan, as part of a five-year memorandum of understanding to give the Jordanians $1.3 billion as they grapple with an influx of refugees and the threat of terrorism brewing on their border. But the friendly occasion couldn’t erase Jordanian disagreements about Trump’s recognition of Jerusalem as the capital of Israel.

“We have different views on Jerusalem, but we share the commitment to peace,” Jordanian Foreign Minister Ayman Safadi. “To Jordan, the two-state solution that guarantees the establishment of a Palestinian state on June 4, 1967 lines with East Jerusalem as its capital and that lives in peace and security with a recognized and accepted Israel is the only path to comprehensive peace.”

The 1967 lines refer to the borders of Israel, prior to the Six Day War, when Israel launched a preemptive attack against amassing Arab neighbors that resulted in the capture of the Gaza Strip, East Jerusalem, and the West Bank. Israeli Prime Minister Benjamin Netanyahu regards the 1967 borders as leaving Israel in an “indefensible” position relative to its neighbors.

“We will be very generous on the size of a future Palestinian state,” Netanyahu told Congress in a 2011 address. “But . . . the border will be different than the one that existed on June 4, 1967. Israel will not return to the indefensible lines of 1967.”

Tillerson downplayed the significance of Trump’s Jerusalem announcement, and emphasized that the policy change allows for the Israelis and Palestinians to negotiate key details.

“I think it’s important to note that when President Trump made his decision to recognize Jerusalem as the capital of Israel, he first committed to respecting Jordan’s role as the Custodian of the Holy Sites,” he said. “And secondly, he made clear that the positions on the final boundaries or borders of Jerusalem is a matter that’s left for the parties to negotiate and discuss and would be dealt with in the final status of issues, all of which are subject to negotiation.”

He declined to say how Trump’s peace plan might address, or avoid, those issues. “I don’t want to get in front of the president or his team that’s been working on that,” Tillerson said. “I have seen the plan, the elements of the plan. It’s been under development for a number of months. I have consulted with them on the plan, identified areas that we feel need further work.”