(CNN) US special envoy for Syria and the Global Coalition to Defeat ISIS Jim Jeffrey said Tuesday that he was not consulted or advised in advance on President Donald Trump's decision to pull US troops from northeastern Syria.

"I was not personally consulted," Jeffrey said in response to a question from Democratic Sen. Bob Menendez of New Jersey. Asked by Utah Republican Sen. Mitt Romney if he was "advised about the decision to withdraw all US troops following that (Turkish President Recep Tayyip) Erdogan call," Jeffrey said: "That specific decision, I was not, in advance."

Jeffrey reiterated that the US had told Turkey not to proceed with the incursion against America's Kurdish allies in the fight against ISIS, saying the operation was not "inevitable" and that Turkey's subsequent incursion into the area has been "really tragic."

'Really tragic'

"Turkey has not really gained all that much from this, as I said, but in the process has scrambled the entire northeast, undercut our efforts against ISIS and brought in the Russians and the Syrian regime forces in a way that is really tragic for everybody involved," Jeffrey told the Senate Foreign Relations Committee.

Jeffrey testified in the face of unusually united bipartisan anger about Trump's decision on Syria and a push by the GOP leadership to reverse the decision. Lawmakers questioned the impact Trump's decision has had on America's allies, US global standing and on the relationship with Turkey -- a NATO ally that some lawmakers described as more like a foe.

The envoy's testimony came as the 120-hour "pause" period negotiated between the US and Turkey came to a close. US officials have indicated that the SDF and Turkey have upheld their obligations to the agreement. Jeffrey also spoke shortly after Erdogan and Russian President Vladimir Putin announced a wide-ranging agreement , including joint patrols.

Senate Majority Leader Mitch McConnell announced Tuesday that he will introduce a resolution urging Trump "to end the drawdown," citing the "grave consequences of US withdrawal." He spoke shortly before a US-brokered ceasefire between Turkish and Kurdish forces ended.

McConnell's resolution condemns the Turkish invasion into Syria, asks Trump to rethink his invitation to Erdogan to visit Washington and recognizes the Kurds for their role in fighting for the US against ISIS.

At the hearing, senators on both sides of the political divide described the President's decision as precipitous. Some described it as a "blunder" and a "stain" on the US reputation. Virginia Democratic Sen. Tim Kaine noted that 176,000 Kurds have been displaced, half of them children.

Sen. Ted Cruz, a Texas Republican, raised fears of the "risk of a genocide" if Turkey decides to move more aggressively against the Kurds.

Lawmakers also pointed to the damage to the fight against ISIS, the danger that more than 10,000 ISIS prisoners could escape. Jeffrey appeared to confirm that about 14,000 to 18,000 ISIS fighters remain at large in Iraq and Syria, despite administration claims of victory over the terrorist group.

Asked how many hardened ISIS fighters had escaped, Jeffrey said the numbers were in the dozens, "but that could change." He said that for now, the US has no idea how those escaped ISIS fighters will be tracked, accounted for and recaptured.

'Not believable'

Florida Republican Sen. Marco Rubio pointed out that the Trump administration's three major priorities in Syria -- preventing an ISIS resurgence, gaining US leverage in any political solution in Syria and pushing for the withdrawal of all Iranian forces -- have all been undermined by the decision to pull back troops.

Republicans and Democrats questioned Jeffrey about the erosion of US standing in light of what some lawmakers described as a betrayal of the Kurds. Jeffrey said the US would work to maintain a relationship with the Kurds. Many asked about the benefits to Russia and Iran, who now stand to wield even greater influence in Syria.

After Jeffrey stressed that the US position is that the future of Syria is up to the Syrian people, not actors like Iran, Sen. Jeanne Shaheen of New Hampshire pushed back. "We're not there anymore," she said. "Russia and Iran are."

Jeffrey repeatedly refuted arguments linking the withdrawal of US troops from northeastern Syria to Turkey's decision to attack the Kurds, saying it would have happened regardless. Senators were incredulous.

Maryland Democratic Sen. Ben Cardin asked Jeffrey if he really believed that "Turkey was going to do this current engagement even if American troops were in the region, making it very likely there would've been a conflict between two NATO allies in northern Syria? That's not believable!"

Jeffrey said, "If US troops had been given the order to stand and fight against a NATO ally, I think you're right, the Turks may have thought twice. They have never been given that order."

Pressed by Cardin on Turkey's potential war crimes, Jeffrey said that "Turkish-supported Syrian opposition forces who are under general Turkish command in at least one instance did carry out a war crime and we have reached out to Turkey to demand an explanation."

Earlier Tuesday, a senior administration official told reporters that the Turkish supported forces "seem to be following orders because all of them have highly professional Turkish advisers with them making sure they're not doing anything wrong."

Deputy Assistant Secretary of State for European and Eurasian Affairs Matthew Palmer and Jeffrey both denied that anyone had ever discussed the Trump Organization's business interests in Turkey with them.