Hungarian anti-terrorist police have detained six people who were in possession of automatic weapons or suspected of producing bombs suitable for terrorist attacks, the head of the unit said on Tuesday.

Police detained four people found to be heading towards the capital Budapest with explosives in their car, Janos Hajdu, Director General of the Counter Terrorism Centre, told the state television channel M1.

In a subsequent house search, police found a bomb-making laboratory with "explosives and devices that were suitable for killing people to the utmost extent", Hajdu said.

He gave no details of the suspects' identities or motives, except to say that the case had "international threads".

He also said police had found two other people with submachine guns, ammunition and silencers in their car, but again provided no further details. Counter Terrorism Centre officials were not immediately available for further comment.

M1 said two of the suspects had been formally placed under arrest, and a court would decide on the others on Wednesday.