(CNN) President Donald Trump reiterated US support for Turkey as a "close, long-standing" partner, during a phone call with Turkish President Recep Tayyip Erdogan on Tuesday.

It was the two leaders' first conversation since Trump took office in January.

Trump welcomed Turkey's efforts in the battle against ISIS, according to a White House readout of the conversation, and spoke of both countries' commitment to fighting terrorism "in all its forms."

Turkish President Erdogan (L) spoke to US President Trump on Tuesday for the first time since Trump's inauguration.

But areas of ongoing tension were notably absent from the readout, including the latter's extradition request for exiled cleric Fethullah Gulen and US support for Kurdish groups in Syria

"Unpleasant issues that aren't mentioned include the future of Syria, who leads it, US relations with Iran, and all these are important in terms of the future of Turkey-US relations," Research Fellow at Sydney's Lowy Institute Rodger Shanahan said.

"They're trying to highlight the issues of common interest, which aren't that many, which is why they mention the Islamic State."

Turkey-US relations cool

The relationship between Turkey and the US has grown increasingly complicated since a foiled coup in Turkey in July 2016. In response to the coup, Erdogan cracked down on the military and judiciary

JUST WATCHED Turkey welcomes more refugees Replay More Videos ... MUST WATCH Turkey welcomes more refugees 01:33

Erdogan demanded the US hand over Gulen, whom he blamed for the coup attempt, but the Obama administration asked for proof of his involvement.

Trump praised the Turkish leader's handling of the coup in a July interview with the New York Times

"I give him great credit for being able to turn that around," he said.

The Trump administration's controversial travel ban, enacted in January 2017, has become another point of difference between the two countries.

Turkey's Deputy Prime Minister Mehmet Simsek posted on his official Twitter on January 29 that refugees were welcome in Turkey

"We'd happily welcome global talent not allowed back into #USA," he wrote.

Safe zones

But Trump will need close relations with Turkey if he is going to enact one of his campaign promises to create "safe zones" in the war-ravaged country of Syria.

The Trump administration has yet to detail exactly what the safe zones will entail but, given Turkey's close proximity and military involvement, the US President will need their help.

"Trump's safe zone plan relies on Turkish cooperation and Trump has said unequivocally there will be safe zones," Shanahan said.

"There's a potential political win-win in this and Erdogan would know that it's a bone he could throw Trump for better relations at a relatively minimal cost."