The United States said Wednesday it gave technical assistance to Moldovan authorities over the seizure of a quantity of the radioactive substance Uranium-238 from suspected traffickers.

"We congratulate the Moldovan Ministry of Interior for its work in thwarting what was a serious smuggling attempt," Mark Toner, a US State Department spokesman, told reporters.

"And we did, in this case, offer law enforcement and technical assistance to the Moldovan Ministry of Interior," Toner said, adding that an FBI team had helped the Moldovan police with their technical analysis.

Police found 1.8 kilograms (four pounds) of the uranium isotope in a garage in the capital Chisinau where it was under guard and in a special container, said interior ministry spokesman Chiril Motpan.

Motpan said that the radioactive substance had been brought to Chisinau via contraband and the people linked to the operation wanted to sell it for nine million euros (11 million dollars).

Toner said preventing nuclear smuggling was a priority for President Barack Obama's administration.

"The US government continues to work with partners worldwide to thwart nuclear smuggling cases, providing assistance with investigations, provisions of radiation detection equipment, training and legal assistance, to increase sentencings for these crimes," he said.