Protesting Greek farmers are set to continue their strike action at the common border with Bulgaria, the Kulata-Promachonas crossing having been severely affected since Monday.

Greece's other neighbors are also affected by blockades as farmers are venting their anger at the Athens government which plans on scrapping subsidies and reforming the social insurance system.

Between Monday noon and late on Tuesday, only cars and buses were able to move both ways across the border at Kulata-Promachonas.

Some transit TIR trucks were granted passage by demonstrators at around 22:30 local time (EET), but border police officials say only a third of the trucks made it through the border crossing before it was closed to them again at around 01:30 on Wednesday.

At 08:40, movement of cars and buses was also halted both ways, Focus News Agency quotes officials as saying.

Another border checkpoint, Ilinden-Exochi, was expected to be closed to all vehicles at 11:00 on Wednesday, as that was the hour demonstrators have communicated to police.

However, the development took place as early as 10:00. Cars and buses are to be allowed passage through Ilinden-Exochi between 15:00 and 17:00 on Wednesday.

The Bulgarian Red Cross is providing food and water to stranded drivers and passengers on the Bulgarian side of the border, and the organization has said it will ask Greek border police to allow its staff to do the same on the Greek side.

Bulgaria's Road Infrastructure Agency on Monday said it had dispatched chemical toilets for the drivers, some of whom have been waiting for nearly two days.

Foreign Minister Daniel Mitov on Wednesday said Sofia can only use "diplomatic pressure" to look for a solution.

He told private national NOVA TV station Bulgaria is using "all instruments" it has to handle the situation and has referred the case to the EU Commission.

On Tuesday, Bulgaria's Transport Minister Ivaylo Moskovski met with Greek Ambassador to Sofia Dimosthenis Stoidis to raise concern about the developments. The envoy, however, is quoted as saying that it is unlikely for the blockades to be lifted before Febuary 04, Thursday, when a general strike is scheduled.

Separately, Prime Minister Boyko Borisov held a telephone conversation with Greek counterpart Alexis Tsipras calling on the government in Athens to take urgent measures.