Romanian authorities have seized 15 truckloads of imported Dutch tulips, turning back three of these to suppliers in the Netherlands because the flowers were allegedly contaminated with dangerous bacteria.

It was the second seizure made by Bucharest on Dutch tulips in a week incensing a politician from the Netherlands.

Dutch Member of the European Parliament Esther de Lange, who doubts the bacteria claim, accused Bucharest of blackmail. She suspects that Romania is retaliating over Dutch opposition to include the country in Europe's visa-free Schengen zone.

The Netherlands wanted Romania and Bulgaria to fight corruption first before they are included in the Schengen Area, where passport checks are not necessary in travel to and from 25 European states.

The Dutch economic affairs ministry has asked for an explanation on the seizure.

The Netherlands is the main supplier of flowers to Romania, with exports totaling nine million bulbs last year worth $934,000. The Dutch suppliers denied there are bacteria in their flowers.

"There is absolutely no question of any bacteria being present," a spokesman for the Dutch flower auctions told news agency ANP, according to Dutchnews.nl.

Romania's blockade of Dutch tulips is being linked to the Netherlands' opposition to include it in the Schengen zone.