Press TV - A US special envoy tasked with resolving the diplomatic crisis between Qatar and the Riyadh regime and a number of its allies has quit his post, citing "unwillingness" of regional leaders to engage in dialogue.

The US-based CBS News television network reported on Tuesday that Anthony Zinni, a retired US Marine General, resigned after realizing he �could not help resolve� the row and a �viable mediation effort� to solve the dispute had failed to materialize.

Saudi Arabia, the United Arab Emirates, Bahrain and Egypt all cut off diplomatic ties with Qatar on June 5 last year, after officially accusing it of �sponsoring terrorism.�

The administration of the Saudi-backed and former Yemeni president, Abd Rabbuh Mansur Hadi, Libya, the Maldives, Djibouti, Senegal and the Comoros later joined the camp in ending diplomatic ties with Doha. Jordan downgraded its diplomatic relations as well.

Qatar's Foreign Ministry later announced that the decision to cut diplomatic ties was unjustified and based on false claims and assumptions.

On June 9, 2017, Qatar strongly dismissed allegations of supporting terrorism after the Saudi regime and its allies blacklisted dozens of individuals and entities purportedly associated with Doha.

Later that month, Saudi Arabia and its allies released a 13-point list of demands, including the closure of Al Jazeera television network and downgrade of relations with Iran, in return for the normalization of diplomatic relations with Doha.

The document containing the demands by Saudi Arabia, Egypt, the UAE and Bahrain also asked Qatar to sever all ties with the Muslim Brotherhood and the Lebanese Hezbollah resistance movement.

Qatar rejected the demands as "unreasonable."