BEIRUT (Reuters) - Syria’s Foreign Ministry on Monday denounced comments by Qatar that it will continue to back rebels against Syrian President Bashar al-Assad as merely an attempt “to raise the morale of the terrorist groups” in the face of army advances.

Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman al-Thani told Reuters in an interview on Sunday that Doha would continue to arm Syrian rebel groups even if U.S. President-elect Donald Trump were to end Washington’s support for them.

Sheikh Mohammed’s remarks showed “the Qatari regime is one of the sources of extremism, terrorism and takfiri thought,” Syrian state news agency SANA reported, citing a Foreign Ministry statement.

Takfir is the labelling of other Muslims as non-believers, a practice that has become a central element of most jihadist groups’ ideologies. The term “takfiri” is commonly used by opponents of jihadist groups to describe the latter’s way of thinking.

Qatar is one of the leading supporters of the insurgency against Assad, joining other Gulf monarchies, Turkey and the United States to supply arms and training to some rebel groups that they say have been vetted.

Damascus regards all the rebels fighting to oust Assad, including both jihadists and nationalist groups, as terrorists. The Syrian army and its allies have recently advanced in Aleppo, the insurgents’ most important urban stronghold.

The Syrian government is supported by Russia’s air force, Iran and Shi’ite Muslim militias from Lebanon, Iraq and Afghanistan.

(Expands on definition of “takfiri” for clarity)