President Donald Trump held a telephone conversation with President Recep Tayyip Erdogan of Turkey on Wednesday afternoon in which he urged caution for Turkey’s military incursion into Syria and called for Turkey to “avoid any actions that might risk conflict between Turkish and American forces.”

However, Trump appears to have stopped well short of demanding Erdogan halt the operation against Syrian Kurds.

According to a White House readout of the call, Trump “relayed concerns that escalating violence in Afrin, Syria, risks undercutting” shared American-Turkish goals in Syria, including the permanent defeat of the Islamic State and the return of Syrian refugees.

“President Trump invited closer bilateral cooperation to address Turkey’s legitimate security concerns. The leaders discussed the need to stabilize a unified Syria that poses no threats to its neighbors, including Turkey,” said the White House.

Trump also reportedly told Erdogan he has concerns about “destructive and false rhetoric coming from Turkey,” by which he might have been referring to some of Erdogan’s trenchant public remarks after the United States first expressed reservations about the Syrian operation, or possibly Erdogan’s accusations that the U.S. has been supporting terrorism by arming the Syrian Kurds to fight ISIS. In Erdogan’s account of the phone call with Trump, he said he urged the U.S. to stop sending weapons to Kurdish militia forces in Syria.

Trump also brought up the status of American citizens and local employees “detained under the prolonged State of Emergency in Turkey,” which has been in progress since the attempted coup against Erdogan in July 2016.

Vice President Mike Pence conveyed “deep concerns” about U.S. citizens arrested in Turkey during a meeting with Prime Minister Binali Yildirim in November, including Pastor Andrew Brunson, who was jailed in October 2016 on accusations of supporting Turkish Imam Fethullah Gulen. Prosecutors later accused Brunson more directly of conspiring with Gulen to overthrow the Erdogan government. Erdogan has personally offered to trade Brunson for Gulen, who Turkey wishes to extradite from the United States, leading critics to accuse Turkey of holding the American pastor hostage.

“The two leaders pledged to improve the strategic partnership between the United States and Turkey, particularly in fostering regional stability and combating terrorism in all its forms, including ISIS, the Kurdistan Workers’ Party (PKK), al-Qaeda, and Iranian-sponsored terrorism,” concluded the White House summary of the Trump-Erdogan call.

The PKK is the violent Kurdish separatist party in Turkey, which the United States recognizes as a terrorist organization, although arguments have been made for delisting it provided the PKK renounces violence. The Turkish government considers armed Kurdish groups in Syria, including those supported by the United States as battlefield forces against the Islamic State, to be allied with the PKK.