JERUSALEM — President Donald Trump’s national security adviser said Sunday that the American military withdrawal from northeastern Syria is conditioned on defeating the remnants of the Islamic State group and on Turkey assuring the safety of U.S.-allied Kurdish fighters.

John Bolton said there is no timetable for the pullout, but insisted the military presence is not an unlimited commitment.

“There are objectives that we want to accomplish that condition the withdrawal,” Bolton told reporters in Jerusalem before heading to Turkey on Monday, where he will be joined by the chairman of the U.S. Joint Chiefs of Staff Gen. Joseph Dunford. “The timetable flows from the policy decisions that we need to implement.”

Those conditions, he said, included defeating what’s left of ISIS in Syria and protecting Kurdish militias who have fought alongside U.S. troops against the extremist group.

Timetable of Trump’s pullout from Syria being questioned Amid questions about the pace of his exit from Syria, President Donald Trump complained on Monday that he’s getting “bad press” for his decision to pull American troops out of the country and insisted he was simply making good on his campaign promise against U.S. involvement in “never ending wars.”

Bolton’s comments were the first public confirmation that the drawdown has been slowed. Trump had faced widespread criticism from allies about his decision, announced in mid-December, that he was pulling all 2,000 U.S. troops from Syria. Officials said at the time that although many details of the withdrawal had not yet been finalized, they expected American forces to be out by mid-January.

“We’re pulling out of Syria,” Trump said Sunday at the White House. “But we’re doing it and we won’t be finally pulled out until ISIS is gone.”

Trump’s move, which led to the resignation of U.S. Defense Secretary Jim Mattis, has raised fears over clearing the way for a Turkish assault on the Kurdish fighters. Turkey considers the Syrian Kurdish People’s Protection Units, or YPG, a terrorist group linked to an insurgency within its own borders.

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National security adviser John Bolton, center, listens as President Donald Trump speaks at a hanger rally at Al Asad Air Base, Iraq, Wednesday, Dec. 26, 2018. In a surprise trip to Iraq, President Donald Trump on Wednesday defended his decision to withdraw U.S. forces from Syria where they have been helping battle Islamic State militants. (Andrew Harnik/AP)

Bolton said the U.S. is insisting that its Kurdish allies in Syria are protected from any planned Turkish offensive — a warning he was expected to deliver to Turkey’s president, Recep Tayyip Erdogan, this week.

"We don't think the Turks ought to undertake military action that's not fully coordinated with and agreed to by the United States," Bolton said. He said that in upcoming meetings with Turkish officials he will seek "to find out what their objectives and capabilities are and that remains uncertain."

Trump has made clear that he would not allow Turkey to kill the Kurds, Bolton said. "That's what the president said, the ones that fought with us."

Here’s what may be driving a US troop withdrawal from Syria A confrontation between the U.S and Turkey, officially NATO allies, would create a geopolitical crisis at the heart of the world’s most powerful military alliance.

Bolton said the U.S. has asked the Kurds to “stand fast now” and refrain from seeking protection from Russia or Syrian President Bashar al-Assad’s government. “I think they know who their friends are,” he added, speaking of the Kurds.

Jim Jeffrey, the special representative for Syrian engagement and the newly named American special envoy for the anti-Islamic State coalition, is to travel to Syria this coming week in an effort to reassure the Kurdish fighters that they are not being abandoned, Bolton said.

Turkey's presidential spokesman called allegations that his country planned to attack the U.S.-allied Kurds in Syria "irrational" and said Turkey was fighting terrorism for national security.

In comments carried by the official Anadolu news agency, Ibrahim Kalin said the Kurdish fighters oppressed Syrian Kurds and pursued a separatist agenda under the guise of fighting ISIS. “That a terror organization cannot be allied with the U.S. is self-evident,” he said.

U.S. Rep. Adam Smith, the incoming chairman of the House Armed Services Committee, told ABC’s “This Week” that the conditions raised by Bolton were “obvious,” and Smith criticized the conflicting messages from the Trump administration.

"We don't want ISIS to rise again and be a transnational terrorist threat and we don't want our allies, the Kurds, to be slaughtered by Erdogan in Turkey," said Smith, D-Wash.

Bolton said U.S. troops would remain at the critical area of al-Tanf, in southern Syria, to counter growing Iranian activity in the region. He defended the legal basis for the deployment, saying it’s justified by the president’s constitutional authority.

US troops to withdraw from Syrian base near Iraq, Jordan that has riled Russia On at least two occasions, the coalition shot down Iranian Shaheed-129 drones in the vicinity of the Tanf garrison.

The U.S. is also seeking a “satisfactory disposition” for roughly 800 ISIS prisoners held by the U.S.-backed Syrian opposition, Bolton said, adding talks were ongoing with European and regional partners about the issue.

Bolton was to have dinner with Israel's prime minister, Benjamin Netanyahu, on Sunday to discuss the pace of the U.S. drawdown, American troop levels in the region, and the U.S. commitment to push back on Iranian regional expansionism.

Bolton was expected to explain that some U.S. troops based in Syria to fight ISIS will shift to Iraq with the same mission and that the al-Tanf base would remain.

Bolton also was to convey the message that the United States is "very supportive" of Israeli strikes against Iranian targets in Syria, according to a senior administration official, who was not authorized to publicly discuss Bolton's plans before the meetings and spoke on condition of anonymity.

Bolton on Sunday also toured the ancient tunnels beneath the Western Wall in Jerusalem's Old City. He watched a virtual reality tour of the historic site and dined there with his Israeli equivalent, as well as U.S. Ambassador to Israel David Friedman and Israel's ambassador to the U.S., Ron Dermer.

Visiting American officials typically avoid holding official meetings in parts of east Jerusalem, which is contested between Israelis and Palestinians. Trump, however, also toured the area in a previous visit.

Israel annexed east Jerusalem after capturing it from Jordan in the 1967 war, a move not recognized by most of the international community. Palestinians seek east Jerusalem as the capital of their future state.

Associated Press writers Zeynep Bilginsoy in Istanbul and Catherine Lucey in Washington contributed to this report.