US President Donald Trump speaks to reporters before leaving the White House in Washington D.C. Sept. 12, 2019. (Photo by Ting Shen/Xinhua)

US President Donald Trump on Wednesday threatened that Ankara will face "devastating" sanctions if high-level discussions between the two sides do not "work it out."

"I think they'll have a successful meeting," said Trump at the White House in a joint press conference with visiting Italian President Sergio Mattarella, referring to Vice President Mike Pence's meeting with Turkish President Recep Tayyip Erdogan scheduled for Thursday.

"If they don't, the sanctions and tariffs and other things that we're doing -- we will do and are doing to Turkey -- will be devastating to Turkey's economy," Trump added.

Pence, along with Secretary of State Mike Pompeo and other senior officials, is heading to Turkey Wednesday, campaigning for a cease-fire for Turkey's offensive in Syria, which has already been denied by Erdogan.

Pence is expected to meet with Erdogan Thursday, when he will "reiterate President Trump's commitment to maintain punishing economic sanctions on Turkey until a resolution is reached," according to a statement released by Pence's office Tuesday.

The United States on Monday rolled out a package of sanctions on Turkey over its military operations in Syria, including blacklisting senior Turkish officials, halting bilateral trade negotiations and raising tariffs on steel imports from the country.

The sanctions came days after Turkey launched military operations targeting the Kurdish forces in several parts of northeast Syria. The Turkish campaign came after Trump's order over the weekend to withdraw around 1,000 US troops from northern Syria.