Bucharest, Romania (CNN) -- After a nearly six-month investigation, authorities launched 70 raids at border crossings and other sites in western Romania Tuesday and detained as many as 100 border police, customs officials and suspected smugglers, police and prosecutors said.
Those detained are suspected of smuggling huge quantities of cigarettes into Romania from neighboring Serbia, and face charges of bribery and facilitating smuggling, prosecutors said.
The raids -- which forced the closure of several crossings on the Romanian-Serbian border -- started at 6 a.m. and were conducted by at least 1,000 anti-corruption prosecutors, police and security forces, authorities said. Many of the suspects' homes were also raided, they said.
Officials confiscated cigarettes worth 500,000 euros ($683,550 U.S.), they added, in raids that were the culmination of a probe that dates back to August.
Police helicopters flew dozens of the suspects to Bucharest for hearings at the National Anti-Corruption Department, authorities said.
Prosecutors said those involved in the smuggling operations easily could make at least 5,000 euros ($6,835.50 U.S.) per illegal shipment, and there have been hundreds of shipments.
Police and customs employee union leaders released a statement following the raids Tuesday, charging that all the smuggling operations were conducted within a well-organized network that had links up to the country's highest political levels and the profits of which possibly financed the ruling political party.
They described the border police and customs employees working at the crossings as the pawns, and said shift bosses, customs managers and some union leaders who collected the bribes were the knights. The intermediate levels were made up of more union leaders and higher customs authority officials, all the way up to the queen, which the union officials charged may be high-ranking members of the ruling political party who appoint customs and border police chiefs.
Romanian Interior Minister Traian Igas told reporters at a news conference after the raids that some of the union leaders are aware of the corruption at many crossings.
"I ask them to position themselves some way in order for us to know whether they're with us or with these people committing illegal acts," Igas said, adding that he does trust the border police and customs employees who are doing their jobs honestly.
Last week, 59 border police and customs employees at the Siret crossing in eastern Romania were arrested on the same charges.
The massive raids come after the interior ministers of France and Germany asked the European Commission to postpone Romania's scheduled entry into the Schengen zone next month because of corruption and security issues. The 25 European countries that are party to the Schengen agreement eliminated internal border controls between member states.
Igas said the smuggling probe and arrests should be a positive signal for Europe that Romania is tackling the issues.