KAPITAN-ANDREEVO, Bulgaria — The spindly observation towers on the Turkish side of this frontier post’s barbed- wire fence stand abandoned, like decaying concrete dinosaurs of a distant Cold War past.

“This border was built to force people to pass through very slowly” from Bulgaria to Turkey, said Nikola Karaivanov, chief of customs at the Kapitan-Andreevo border station. “Now,” he said, “it needs to be changed in the opposite direction” – to control passage into the European Union.

EU officials say that this sprawling border area about 300 kilometers, or 185 miles, southeast of Sofia will soon become one of the EU’s busiest external frontiers: 35 lanes of increasing trade and passenger travel between Turkey and an expanded, 27-member bloc.

How soon may become known next week, when the European Commission reports on progress by Bulgaria and Romania toward joining the EU on Jan. 1. The two Balkan countries are expected to be admitted at the latest by Jan. 1, 2008.

The problem, EU officials warn, is that the Bulgaria-Turkey crossing sits on one of the main illicit routes for narcotics, contraband, and illegal immigration reaching Europe from the Middle East.

The scale of the traffic at Kapitan- Andreevo is already impressive and is certain to grow once Bulgaria joins the EU. In 2005, 1.4 million vehicles, 5 million people, and 7 million tons of cargo crossed here in both directions – a daily average of 3,836 vehicles, 13,699 people and 19,178 tons of goods.

The risk comes from the eventual disappearance of internal border controls in the enlarged EU, combined with corrupt and weak Bulgarian state administration. Weaknesses in one external border would expose the whole system.

“There will be such control here that it won’t be necessary for any other country in all of Europe to control their borders,” vows Kostadin Kadev, the chief of the Kapitan-Andreevo border station, a huge complex of inspection facilities and administrative buildings that covers 18.4 hectares, or 45.5 acres.

However, the Bulgarian public – and Bulgaria’s future EU partners – still need convincing.

Customs officials have a special place in the Bulgarian popular consciousness. Hated for their corruption, they are also the object of jealousy for the power and privileges they are thought to enjoy. Polls consistently show that Bulgarians perceive customs men as the most corrupt public officials. In a survey by Vitosha Research last November, 71.8 percent of Bulgarians questioned said that “nearly all or most” customs officials were “involved in corruption.”

Improvements at the country’s borders are among the many Bulgarian reforms under consideration by EU officials for their progress report next Tuesday. At Kapitan-Andreevo alone, Bulgaria and the EU have spent about $7.5 million over the past three years on new border control facilities, fixing old ones and building new traffic lanes. The facilities and management are being upgraded to meet EU standards. But most Bulgarians are unaware of such improvements.

Others know of the changes but remain critical.

“Now there is no massive crossing of the border by what used to be called ‘wild’ contraband,” said Lyubomir Terziev, a former customs officer who worked at Kapitan-Andreevo in the 1990s. “You can’t deny there is a tightening of discipline and order. But at the same time, the leadership puts those trusted by organized-crime groups inthe positions where they can let through what is needed.”

Bulgarian border officials have been exposed to more corrupting influences than other state officials because of the sudden economic opening of the country following the end of Communism in 1989 and the huge smuggling opportunities created by the embargo imposed on Yugoslavia during the Milosevic era.

As the Center for the Study of Democracy in Sofia put it in a recent report, “The border became a mechanism for redistribution of national wealth on a scale that is comparable only to the process of privatization of state assets.”

Tihomir Bezlov, an analyst who worked on the study, described the enormous corruption on the borders as a natural economic process in a poor country dependent on trade. “Bulgaria is a small country, the economy is open,” he said, “and the equivalent of 60 to 70 percent of gross domestic product moves across a border in one direction or another.”

Payments can range anywhere from the standard thank-you gift of a customs “sandwich” (a bottle of whiskey between two cartons of cigarettes) for a small favor to €10,000, or $12,800, in cash for a container of high-value goods to be taxed based on a lower value, said Terziev, the former customs officer.

According to border officials and private sector representatives, methods of using the border for illicit purposes have evolved significantly in recent years.

The era of paying a border official to lift the road barrier for a vehicle to pass through uninspected is over: Imported goods must all have legal documents now. “Suitcase traders” carrying bundles of consumer goods no longer illegally scramble across land borders in large numbers, and wizened “guide women” no longer charm and bribe their way through border controls on behalf of single busloads of clients’ goods.

The analyst Bezlov said the coming of discount warehouse hypermarkets in 1999 also eliminated much of the demand for smuggled low-priced, low- quality consumer goods from Turkey. In recent years, Chinese goods have also underpriced the Turkish.

Instead, the most significant bribes are now paid directly to top-level state officials by professional smugglers who work on the scale of shipping containers, the study found. This type of contraband, experts say, is far harder to fight than the “lifted barrier.”

“Bulgarian border security will not be at a West European level in 2007,” said Philip Gounev, another analyst who worked on the report. “It will be like Poland or Hungary, with moderate corruption and inadequate budgeting.”

Gounev said weak Bulgarian controls would affect the budgets of the EU and its member states only if smugglers evading value-added or excise taxes on goods bound for the EU began to reroute through Bulgaria. But Gounev saw no reason to think that the Belarussian-Polish border, for example, would be any tougher.

Bulgaria is also a transit country on one of the main smuggling routes for heroin to Europe, the so-called “northern Balkan route” from Afghanistan. The “southern Balkan route” enters the EU from Turkey through Greece and on by boat to Italy.

“It can be expected that the Balkan routes will remain the most prominent supply routes for heroin in the coming years,” according to Europol, the European police agency.

Bulgaria is also a major transit country for illegal immigration to the EU. Europol identifies Istanbul, 265 kilometers southeast of Kapitan-Andreevo, as one of the top three “departure points or assembly points for the onward journey to the EU.”

Then there are the duty-free shops. In Bulgaria, they play a “major role” in the smuggling of excise goods like tobacco, alcohol, and gasoline, according a 2006 report by the U.S. State Department on international money laundering and financial crimes. “Credible allegations have linked many duty-free shops in Bulgaria to organized-crime interests involved in forced prostitution, the illicit drug trade, and human trafficking,” the report says.

Duty-free gasoline stations are also a major cause of lost state revenue, costing Bulgarian taxpayers at least 100 million levs, or €51 million, a year. For more than 10 years, three such stations have operated in the area around Svilengrad, the main town near Kapitan-Andreevo.

The State Department said that attempts by the Finance Ministry to shut them down had failed because of “political opposition within the ruling coalition.”