Though the Greek authorities have beefed up security measures with the new corps of border guards, which is generally thought successful, crime is still thriving on the border, according to a conference held recently at Thrace University. THRACE: This region has the most serious problems with border crime. To the east, Evros is an strategic pass for illegal immigrants and a major path for heroin traffickers, despite being the most closely guarded border in Greece. To the north, gangs smuggle women through Bulgaria to Greece and on to Western Europe. PROSTITUTION: In 2001, cases of procuring prostitutes increased by 270 percent compared with the previous year, and arrests of human traffickers in Thrace rose by 50 percent, despite a 4.5-percent fall in the number of migrants arriving in the area. This decrease, however, is artificial and results from the abolition of visas for Bulgarians and Romanians, according to the Rhodope police chief, Christos Bratzoukakis, and his counterpart in Serres, Dimitris Intos. They presented statistics showing that in Thrace in 1999 there were 19 arrests of women forced into prostitution, a number which rose to 49 in 2000 and 93 in 2001. In the prefecture of Serres alone in the past three years, there were 50-60 arrests a year of migrant smugglers and procurers of women for prostitution. ILLEGAL IMMIGRATION: The prefectures of Kastoria and Florina (which are close to Albania) and the prefecture of Thrace are still the chief entry points for economic refugees. In 2000 in Thrace 21,664 foreign migrants were arrested, and last year another 20,771 were arrested. In the same area in 2000 there were 123 cases of smuggling, involving the arrest of 191 people and confiscation of 116 vehicles. The Rhodope police chief believes that border crime prevention conventions signed with countries such as Albania, FYROM, Bulgaria, and more recently with Turkey are ineffective because those countries are unable to control the flow of migrants coming from their territory.