A Syrian government delegation heading to peace talks in Switzerland was held up for hours in Athens after a Greek firm refused to refuel the plane they were travelling in.
Vassilis Alevizopoulos, head of Greece's Civil Aviation Workers Union, said a fuel firm had refused to refuel it because of European Union sanctions against Syria.
Syrian state television issued a terse statement saying the four-hour delay could cause foreign minister Walid al-Moualem to miss his meeting with UN chief Ban Ki-Moon. It said the plane had later resumed its flight.
Greek police have asked for permission to check the phone records of Golden Dawn politicians as part of an investigation into the killing of a anti-racism rapper by a supporter of the far-right party, police said.
The government has already asked judges to investigate links between the party, which won 7% of the vote in the last election, and the death of Pavlos Fissas, who was stabbed to death on Tuesday night, after being ambushed a crowd of 30.
A police officer told Reuters that they want to establish if Golden Dawn politicians or local party chiefs called supporters on the evening of the death.
The government says it believed the party is a criminal organisation and a threat to public safety.
Greek Prime Minister Antonis Samaras has called for calm during an "extremely critical time" for the country after an anti-fascist rapper was fatally stabbed by a man allegedly linked to far-right party Golden Dawn.
Samaras said in a televised address to the nation: "This government is determined to not allow descendents of Nazis to poison society, to commit crimes, to terrorise and to undermine the foundations of a country that gave birth to democracy."
Golden Dawn, Greece's third most popular party, insisted it had nothing to do with the killing and has condemned the attack.
Those who accused the party were "wretched sycophants" trying to win votes, the far-right party added.
Nikos Dendias, public order minister, said emergency legislation would be tabled that would seek to outlaw the group, adding that the attack showed "in the clearest way (the party's) intentions."
Prominent ant-fascist Pavlos Fyssas, 34, died after around 30 Golden Dawn supporters attacked him and seven of his friends.
A 45-year-old man has allegedly confessed to the stabbing of Fyssas' - also known as Killah P - and was pictured today being escorted by a policeman as they left the prosecutor's office in Piraeus, near Athens.
Protests and violence erupted after the death of the anti-fascist campaigner with Greece's deputy Prime Minister Evangelos Venizelos saying the group must be treated as a "criminal organisation".
Thousands of protesters have took to the streets of Athens to protests the murder of anti-racism rapper Killah P.
A 45-year-old man arrested over the alleged stabbing of an anti-fascist activist has admitted being a follower of Greece's far-right group Golden Dawn, according to media reports.
Golden Dawn has condemned the killing and denied having any involvement, accusing people of using the "tragic event" for political ends.
The far-right party, which has 18 MPs in the Greek parliament, has repeatedly been accused of violence towards its political opponents.
A 34-year-old man killed in a knife attack in Athens has been named by local media and political organisations as the campaigner Paul Fyssas.
Fyssas was well known as an anti-fascist activist and a rapper who used the stage name Killah P.
His family were also known in the area for their left-wing activism, according to a Greek news agency.
Police in Greece have arrested a man in connection with the fatal stabbing of an anti-fascist campaigner in Athens in the early hours of this morning, according to local media reports.
Paul Fyssas, who is also known by his rapper name Killah P, is reported to have got into an argument with the suspect after a football match in a late-night cafe in the Piraeus suburb.
Witnesses say the 34-year-old activist and his friends were attacked by a gang of 10-15 individuals outside the venue. Fyssas was reportedly pursued by a car before the driver approached him and stabbed him several times.
Several Greek newspapers report that police have stormed the offices of the right-wing Golden Dawn party following the incident, and that the party has denied any involvement.
An earthquake has rattled the Greek capital Athens causing buildings to shake for several seconds, witnesses have reported.
There were no immediate reports of casualties or damage, police and fire brigade officials said.
Data from the US Geological Survey showed that the magnitude 5.1 quake struck north-east of Patras at a depth of 9.7 miles.