A tense stand-off is continuing in the Greek capital, Athens, more than 12 hours after foreign gunmen seized a bus carrying about two dozen passengers.
Police parked a white bus across the street to prevent escape
Two Albanians hijacked the bus at dawn and threatened to bomb the bus if they were not given safe passage to Russia.
Hostages were released at regular intervals throughout the day, with reports saying that seven remain.
The crisis led Greek Prime Minister Costas Karamanlis to delay his departure for an EU summit in Brussels.
Hostage Stella Matara told Greek television in a mobile phone call from the bus that the gunmen wanted a driver to take them to the airport.
The original driver escaped during the initial confusion, taking the keys with him.
They would release all the women when the driver arrived, she said.
"At the airport, they want a plane to take them to Russia, and then they will release the rest of the hostages," Reuters news agency reported her as saying.
So far they had not harmed the hostages, Ms Matara said.
"They have guns, they have dynamite. I can see them in front of me. I don't know what will happen later because both they and us are now very, very nervous."
Members of Greece's elite anti-terrorist units, who were trained to provide security for this year's Athens Olympics, are surrounding the bus.
The BBC's Malcolm Brabant, who is at the scene, says that a senior government source has confirmed that the two men were Albanian nationals whose primary demand was to be allowed to leave Greece.
The Greek authorities are determined to continue their policy of peaceful negotiation, which appears to be having some success, our correspondent adds.
One of the released hostages told a Greek radio station the hijackers have demanded a 1m euro (£690,000) ransom, the AFP news agency reported.
Police said they had no knowledge of the demand.
The bus was seized at about 0600 (0400 GMT), shortly after the men boarded the bus in the suburb of Pikermi.
They closed curtains and fired shots through the roof, stopping the bus outside the Moratone nightclub in another suburb, Gerakas.
The bus is on the Marathon Road, a key feeder route close to a turning for Athens airport.
Greek special forces are highly trained in counter-terrorism
Police and hostage negotiation teams quickly moved into position, sparking more gunfire, although no one was injured.
Amid confusion the bus driver, the ticket inspector and a passenger managed to escape.
"I stopped the bus, I opened the doors in order for the people to come out, I opened my door as well and I pulled one woman out," the driver, who was not named, told Greek television.
Nikos Koutsogiorgos, head of bus operator KTel, told the BBC the driver had acted in line with anti-terror training.
Five years ago, Greece witnessed two bus hijackings within two months.
In both cases, an Albanian man took control of the vehicle, demanding money and safe passage to Albania.
Both hijackers were shot dead by security forces. In one of the incidents, a passenger was also killed.