The treaty, signed last year but still dependent on parliamentary approvals, passed quietly in Germany's main chamber on Thursday despite major differences between Prague and Berlin over EU responses to refugee arrivals.

Backing came from the conservatives and Social Democrats in Chancellor Angela Merkel's grand coalition. The cooperation treaty was opposed by the opposition Left party, with the Greens abstaining.

Günter Baumann, a conservative federal parliamentarian from the Erz Mountain region in Germany's Saxony state, bordering the Czech Republic, described the treaty as a "single but important building block" in Europe's security mosaic.

It would create a new basis for "more effective" joint police and customs work on both sides of the 646-kilometer (400-mile) German-Czech border, he said, and incorporate jointly staffed headquarters located at Schwandorf in Bavaria and Petrovice in the Czech Republic.

The treaty now hinges on approval by Germany's upper house of parliament, the Bundesrat.

Czech-German passport controls were removed in 2007

Crystal meth region

Another Christian Democrat (CDU), German interior ministry state secretary Günter Krings said Czech and German officers would be able to operate jointly on both sides of the border, for example, in vehicle searches and passports checks.

The border region has a reputation for heavy smuggling of the synthetic drug crystal meth produced in illegal Czech laboratories, once in small quantities and now in kilograms.

Saxony's LKA criminal investigations office said earlier this month that the drug first appeared in the Erz Mountain region in 1998. Since then, its distribution has spread across Germany and other parts of western Europe.

Postal secrecy problematic

Bavarian LKA expert Sigrid Kienle said smugglers were increasingly using regular mail services, but the strict German postal secrecy law hindered police detection.

Without judicially proveable suspicion, police could not "simply take a drug-sniffing dog into a postal distribution center or x-ray suspect packages, she said.

"That is for us a giant problem," she said.

"The physical and psychological results are frightful," she added, referring to crystal meth consumers at "all societal levels."

Modernizing legal basis for policing

The policing treaty signed in April 2015 by the German and Czech Interior Ministers Thomas de Maizìere and Milan Chovanec modernizes arrangements reached by both nations in 2000.

That was before the Czech Republic became an EU member in 2004 and well before Prague began applying Schengen open-border arrangements in 2007.

The new treaty should also make it easier when investigators and prosecutors lodge requests for cross-border judicial assistance.

The Czech Republic is one of four "Visegrad" central European countries that in recent months have resisted Chancellor Angela Merkel's urgings to take in asylum seekers, and instead demanded strict border protection.

ipj/kms (dpa, AFP)