Border guards in eastern Poland are reporting a sharp drop in the number of visitors from some of its eastern neighbours because of new frontier controls.
Border crossings in Belarus are almost deserted
The controls include a visa regime for visitors from Russia, Belarus and Ukraine.
Previously, travellers from the former Soviet republics had been able to enter Poland for three months with just a passport.
Now they will have to apply for a visa in advance at Polish consulates.
The move is part of Poland's preparations to join the European Union in May next year.
He says the tighter controls will mostly affect people living close to the border who engage in small-scale cross-border trade, some of it in black-market items such as alcohol or cigarettes.
Experts say the trade - estimated at 700 million euros in 2002 - could collapse under the new visa regime.
This seemed to be confirmed by evidence on the ground.
guard spokesman Colonel Andrzej Wojcik told Reuters news agency that only 500 people had crossed the Bug river sector of the border in the first 12 hours of the new visa regime, compared with 30,000 in the previous 24.
"Traffic isn't completely frozen, but it's very low... It
will definitely grow [but] it might not return to the previous levels," he said.
'Business will decline'
Polish Foreign Ministry spokesman Boguslaw Majewski said official trade would not be affected by the changes.
The issue is a tricky one for Poland, the BBC's Adam Easton in Warsaw says, as it does not want to be seen as turning its back on its eastern neighbours.
Our correspondent says Poland's eastern border is now in effect the eastern boundary of the EU. Citizens of Ukraine and the Russian enclave of Kaliningrad will be able to receive multiple-entry visas to Poland for free, while Belarusians and other Russians will have to pay.
But small traders are unhappy with the fees - ranging from 10 euros ($11.70) to 50 euros - which they say are expensive given the current standard of living.
"From Wednesday, we will lose our living," Irina, from the Belarusian city of Brest, told the Associated Press news agency.
"Every day I travel by train to Poland to sell my goods and I take back food to Belarus."
Across the border, Poles are also worried by the change.
"Some 99% of our customers are Belarusians," said butcher's shop assistant Krzysztof Falkiewicz. "Business will decline for sure."
Polish officials say that once the visa regime is in place, much tougher controls will be placed on cross-border trade.
Anyone found with contraband alcohol or cigarettes will have their visas cancelled and be banned from entering Poland.
The new measures came as Poland announced its proposed changes to the draft EU constitution, including a request for a mention of Europe's Christian heritage.