U.S. Secretary of State John Kerry’s closed-door diplomacy to broker peace between Israel and the Palestinians has burst into a public spat, with both sides trading blistering criticisms, Republican senators showing up in Jerusalem to argue Israel’s side, and Palestinian demonstrators protesting his visit.

Kerry is on his 10th visit to the region to try to craft a peace treaty that would create a Palestinian state alongside Israel.

He met for three hours on Friday with Israeli Prime Minister Benjamin Netanyahu. Later in the day, Kerry traveled to Ramallah, West Bank, to speak with Palestinian President Mahmoud Abbas. Although battered by sniping from all sides, Kerry remained upbeat — at least publicly.

Asked if he was making progress, Kerry replied that progress is being made every day.

Earlier, about 150 Palestinians demonstrators marched through the streets of downtown Ramallah to protest Kerry’s visit. They carried Palestinian flags and signs that said: “The northern, central and southern Jordan Valley are a genuine part of Palestinian sovereignty.” The West Bank’s Jordan Valley is a strategic area along the border with Jordan that Israeli hardliners, including members of Netanyahu’s Likud Party, say must be annexed by Israel for its own security.

So far, the two sides have engaged in about 20 rounds of negotiations, which have entered a more intense phase.

The goal is for the framework, or series of guidelines, to address all core issues, including borders between Israel and a future Palestinian state, Palestinian refugees and conflicting claims to the holy city of Jerusalem. No agreement on a framework is likely during Kerry’s visit.

Political activist Abdallah Maslamani said a proposed framework that would guide negotiations on a deal protect the security interests of “the terror state of occupation,” a reference to Israel.

One night earlier, the digs were coming from the other side. Netanyahu lashed out at Abbas, accusing him of embracing terrorists “as heroes.’”

Netanyahu criticized Abbas’ homecoming for more than two dozen Palestinians released earlier this week from Israeli jails where they had served time for deadly attacks against Israelis. The Palestinian leader never condoned their crimes, but Netanyahu took offense.

“To glorify the murders of innocent women and men as heroes is an outrage,” Netanyahu said, dampening hope that much progress would be made on the contours of an eventual peace accord during Kerry’s visit.

On Friday, Saeb Erekat, the chief Palestinian negotiator, responded to Netanyahu remarks, saying that even if Abbas were Mother Teresa, the Israelis would find a way to accuse Abbas of terrorism so he wouldn’t have to accept the Palestinians’ demand for a state in lands Israel captured in 1967.

Even in Jerusalem, Kerry couldn’t escape domestic politics interfering with international diplomacy. Three Republican senators held a news conference after meeting with the Israeli leader, reiterated his concerns, thereby emboldening Netanyahu’s position right before Kerry’s delicate talks with Abbas.

“Prime Minister Netanyahu has serious, serious concerns about the plan that has been presented to him — whether it be the ability of Israel to defend its borders, the viability of a Palestinian state and their intentions and their actions toward the state of Israel, and particularly on the overall security — whether it’s boundaries, areas under Palestinian control,” Sen. John McCain of Arizona said.

McCain was in Israel with fellow Republican Sens. John Barrasso of Wyoming and Lindsey Graham of South Carolina, following their visit to Afghanistan.