A Syrian government delegation heading to peace talks in Switzerland was delayed in Athens on Tuesday, Jan 21, when a Greek firm refused to refuel their plane, citing an EU trade embargo, the head of Greece's Civil Aviation Workers Union said, according to Reuters.

Syrian state television issued a terse statement saying the plane was grounded in Greece and that the delay could cause Syrian Foreign Minister Walid al-Moualem to miss his meeting with United Nations Secretary General Ban Ki-Moon.

The incident is the latest in a series of delays and diplomatic spats in the leadup to the talks, dubbed "Geneva 2", which are due to start on Wednesday between President Bashar al-Assad's government and opposition figures to end their three-year conflict.

"The delegation's plane landed at Athens international airport and was prevented from refueling," Syrian state television said, adding that all airspace permissions had previously been granted for the flight.

Vassilis Alevizopoulos, head of Greece's Civil Aviation Workers Union, said the plane was allowed to land in Athens but the fuel company refused to refuel it because of European Union sanctions against Syria, according to Reuters. He did not give the company's name.

Greece's Foreign Ministry spokesman confirmed the plane had been temporarily detained and said it had since been cleared for take-off, although Greek air traffic controllers and Syrian state television said the plane was still in Athens.

"Counter to the claims of the Greek Foreign Ministry about solving the issue of the Syrian plane ... it has not been permitted to refuel, which has prevented it from taking off," Syrian state television said.