U.S. Secretary of State Rex Tillerson will tackle "Hizbullah's subversive role in Lebanon and the region" during his upcoming visit to Beirut, a U.S. official said.

Tillerson will meet President Michel Aoun, Speaker Nabih Berri and Prime Minister Saad Hariri and this "will represent a real opportunity to confirm our support for Lebanon, which is currently facing several challenges, including defending its borders against terrorists and coping with the huge refugee influx," a senior U.S. State Department official told Kuwait's al-Rai daily in remarks published Sunday.

"This visit also highlights our keenness on Lebanese state institutions, topped by the Lebanese Armed Forces and the Internal Security Forces, who are fighting the Daesh and al-Qaida groups and safeguarding stability in Lebanon," the official added.

"It is also obvious that Tillerson will raise the issue of Hizbullah, which is playing a subversive role in Lebanon and the region," the U.S. diplomat went on to say, noting that "it is unacceptable for such a party to continue to operate outside the authority of the Lebanese state."

"This issue will represent the main topic of discussions between Tillerson and the Lebanese leaders," the U.S. official added.