Talks between Israel and the Palestinian Authority are at a critical stage, President Shimon Peres said Thursday. He called on European countries to lend support to the process.

“The negotiations between us and the Palestinians are approaching the moment of truth,” he declared.

Peres spoke at a ceremony in which he received Letters of Credence from five new ambassadors from Europe. The new ambassadors from the EU, Moldova, Romania, Belarus and Tanzania presented their letters at the President’s Residence in Jerusalem.

Peres’ comments came as United States Secretary of State John Kerry returns to the region. Kerry is expected to put heavy pressure on Israeli leaders to make further concessions to the Palestinian Authority.

Kerry has insisted on an Israeli “gesture” of releasing Palestinian terrorists convicted of murder as part of talks, and has pushed Israel to agree to give the Palestinian Authority control of the Jordan Valley, as well as much of the rest of Judea and Samaria. The latter initiative hit a snag when the PA refused the plan, which would have seen international troops stationed on the Jordanian border for a period of time.

Israeli activists and politicians have increasingly criticized Kerry’s proposals, and have warned that negotiations seem doomed to fail.

On Thursday, nationalist activists reported a last-ditch attempt to prevent the U.S. Secretary of State from reaching Jerusalem. Former Member of Knesset Michael Ben-Ari used his Facebook account to share a call by one of his supporters, urging those who oppose Kerry’s pressure on Israel to drive to Highway 1 before his arrival, and to fake “car trouble” that would block the road, leaving the U.S. diplomat stuck on the highway. Those efforts seem to have failed to materialize, however.

Kerry landed in Israel at around 2 p.m. Thursday. Highway 1 was ordered closed to traffic until 2:30 as he traveled to Jerusalem.