Turkish President Recep Tayyip Erdogan reviews a guard of honor at the presidential palace in Ankara, Turkey, on Feb. 7, 2017. (Reuters)

Turkish President Recep Tayyip Erdogan sought to convince President Trump in a telephone call that arming Kurdish fighters in Syria to fight the Islamic State would be counterproductive to the military effort and damaging to already strained ties between the United States and Turkey, American and Turkish officials said Wednesday.

One of Erdogan’s objectives in the call was to try to persuade Trump to abandon a military-backed proposal to arm Kurdish fighters for an assault on the militants’ self-proclaimed capital, the city of Raqqa. But Trump was noncommittal in Tuesday’s conversation, saying that additional consultations were needed on the Kurdish question, the officials said.

Senior Trump advisers have expressed doubts about the wisdom of arming the Kurds but have not ruled it out. 

Turkey sees the Syrian Kurdish fighters as part of its own Kurdistan Workers’ Party, or PKK, a group the United States and Turkey have labeled a terrorist entity. U.S. support for the Syrian Kurds soured ties between the Obama administration and Turkey and could also complicate the nascent relationship between Trump and Erdogan, which has so far been free of the rancor that characterized Obama’s exchanges with the Turkish leader

Officials said the call was cordial and notably free of fireworks, amid strong indications that both leaders were trying to turn the page. Trump spoke broadly about the importance of strengthening ties with Ankara, U.S. officials said. Hours after the call, Turkey’s semiofficial state news agency announced that CIA Director Mike Pompeo was flying to Turkey this week in what amounted to a high-level sign of U.S. concern for the relationship. 

The CIA declined to confirm Pompeo’s visit. Turkish officials made a point of telling local media outlets that it was Pompeo’s first trip abroad since he became director.  

Erdogan has tried to convince the United States that Turkish-backed Arab fighters in Syria and Turkish troops can carry out the offensive on Raqqa instead of the Kurds.

Early Wednesday, Turkish-backed forces made significant advances toward al-Bab, a Syrian border town occupied by the Islamic State that Turkish forces have struggled to capture for months, Turkish officials and rebel commanders said. 

The Turkish forces and their Arab allies in Syria — part of Turkey’s overall Syria intervention, known as Euphrates Shield — captured areas west and southwest of the town, including a hospital and a strategically important hill, the commanders said. 

 The timing of the military push close to the phone call appeared to be no accident, said Selim Koru, a political analyst at the Economic Policy Research Foundation of Turkey, an Ankara-based think tank. With the United States watching, a “competition” was underway between the Turkish-backed forces and Syrian Kurdish fighters, who are allied with the Democratic Union Party in Syria, he said. 

“Who is the better ground force against ISIS?” Koru said.

Entous reported from Washington. Karen DeYoung in Washington and Zakaria Zakaria in Istanbul contributed to this report.