Iran coach Carlos Queiroz has resigned, citing a lack of support from the Iranian Football Assocation amid a club vs. country row.
The former Real Madrid and Portugal coach took Iran to their fourth World Cup in 2014 and they are currently top of their qualifying group for the tournament in 2018. Iran are also ranked No. 29 in the world by FIFA, the highest in Asia, and were unbeaten in 2016.
With a place at what would be a first-ever successive World Cup appearance within sight, Queiroz announced on social media that he had handed in his resignation.
Queiroz resigned multiple times since his appointment in 2011 only to return to the post, but the 63-year-old coach told the Associated Press that he is serious this time around.
"The federation says it does not have the authority to implement the programme of preparation to qualify for the 2018 World Cup that was agreed upon last year," Queiroz said. "What then can I do?"
A federation representative could not be reached for comment.
The current row was brought to a head during a training camp held by the national team in the United Arab Emirates at the start of the year.
Branko Ivankovic, head coach of leading Iranian club Persepolis and Iran's national team coach at the 2006 World Cup, complained about losing seven players during the middle of the domestic season.
"Queiroz has invited our key players to the training camp while Persepolis should prepare for the AFC Champions League," Ivankovic, who has clashed with his successor in the past, was quoted as saying in Iranian media.
The Croatian added that he would hold Queiroz responsible if Persepolis failed to progress past the first round of the Asian club competition.
Queiroz was unhappy about the comments.
"I can't be in the position that one gentleman in Iran insults and offends me and the federation does nothing," he said. "The fans don't count in Iran and results don't count. There are a few people with power behind the scenes and they are what counts. They are trying to destroy the national team and don't want it to succeed."
Iran are a point ahead of South Korea in Group A in World Cup qualifying with five games remaining. The top two qualify automatically for the 2018 tournament in Russia.
Iran are scheduled to play Qatar and China in March. Ivankovic has been linked with a return to the Iran post after Queiroz's past resignations.
"I should not be fighting against Persepolis and Branko," Queiroz said. "My fight is against China, Qatar, South Korea and Uzbekistan. Branko should be fighting against other Iranian teams."