CANBERRA, Australia (AP) — Three Australians have been arrested in Serbia over the second-largest cocaine haul in Australian law enforcement history, police said on Thursday.

Serbian police alleged the men arrested in a Belgrade hotel foyer on Wednesday "are linked to" the discovery of 1.28 metric tons (1.41 U.S. tons) of cocaine that were seized last April on a Chinese freighter docked in Sydney. The drug haul was worth 500 million Australian dollars ($400 million), police said.

Police said the arrests were made during a "money handover." A Lebanese citizen was detained and charged with having forged identity documents.

The drug was concealed in pre-fabricated steel in more than 2,500 individual blocks and was the second largest cocaine seizure in Australia, Australian Federal Police and the Australian Border Force said in a statement.

"This was a sophisticated concealment, but thanks to our highly trained officers and world-class screening technology, we were able to locate the cocaine and ultimately disrupt a significant international drug operation," Border Force Assistant Commissioner Tim Fitzgerald said.

The largest Australian haul of the illicit drug was 1.4 metric tons (1.5 U.S. tons) found in February last year in a yacht that had allegedly smuggled it from the South Pacific. Six people were charged and face potential life prison sentences.

That larger haul was valued at over A$300 million because of its lower purity than the second-largest haul.

After the Serbian arrests, Australian police executed five search warrants in the national capital Canberra and three towns in New South Wales state. No arrests have been made in Australia, but investigations continue, police said.

Illicit drugs command relatively high prices in Australia, making it an attractive market for international drug networks despite its remoteness.