KIEV (AFP) - Ukrainian security services claimed on Tuesday to have thwarted a plot against the Dutch foreign minister as he paid his respects to the victims of downed Malaysia Airlines flight MH17.

The alleged plot against Mr Bert Koenders dates back to Nov 8 in Kharkiv, eastern Ukraine, where he and a delegation were due to visit a building housing the remains of some of the victims.

The Boeing 777 flying from Amsterdam to Kuala Lumpur was shot down in a remote, rebel-held area in eastern Ukraine in July, killing all 298 people on board.

"We have arrested a very dangerous group of 12 people," the head of the security service, Mr Valentyn Nalyvaychenko, told a press conference.

"We seized weapons, guns and ammunition. They also had mines and explosives in their possession."

Citing information from the interrogation of one of the suspects, he added that those arrested were Ukrainians commissioned by Russian military intelligence to carry out the attack.

Contacted by AFP about the alleged plot, the Dutch justice ministry said it could not confirm anything "at the moment".

A recovery team overseen by Dutch experts carried out a third day of work on Tuesday to recover debris from flight MH17, eventually aiming to return it to the Netherlands.