Qatari diplomats spoke with Hayat Tahrir al-Sham (HTS) on Monday, an official briefed on the developments told Reuters, as regional states race to open contact with Syria's leading rebel faction after its rapid offensive toppled Bashar al-Assad. Qatar plans to speak with HTS leader Mohamed Al-Bashir on Tuesday, the day after he was appointed to lead Syria's transitional administration, the official said. Governments across the region are scrambling to forge new links with HTS and other rebel groups involved in the offensive that seized control of much of Syria in the Middle East's biggest upheaval in generations. Assad fled to Russia, after 13 years of civil war and more than 50 years of his family's rule. Qatar's foreign ministry did not immediately respond to a Reuters requests for comment about the contacts with HTS, a group formerly allied with Al Qaida and which is designated a terrorist organization by the U.S., European Union, Turkey and the U.N. Assad's main regional ally Iran also opened a direct line of communication with rebels in Syria's new leadership, a senior Iranian official told Reuters, citing the need to "prevent a hostile trajectory" between the countries. It was not clear if Iran's contacts were with HTS or another Syrian rebel faction.