Judicial experts from five EUcountries are meeting in Spain to conclude talks on the implementation of a controversial Europe-wide arrest warrant.
The warrant, conceived after the September 11 attacks and due to be implemented in January, aims to replace lengthy extradition procedures but has raised concerns in certain European Union countries.
So far only some EU members have made the warrant national law, including Spain, Portugal and Britain. In, Ireland a Bill is awaiting its second stage reading in the Dáil while France and Germany plan to approve it early next year.
But in Italy, a leading lawmaker has threatened to bring down the government if it honours a pledge to accept the warrant.
Ministers said they hoped agreeing on the technical details would encourage doubters.
"If we sort out the practical issues then those who may not have been as confident will see that this is a robust effective tool, and I'm sure that will do a lot of good," Ms Patricia Scotland, Britain's minister for criminal justice and law reform, said.
Spanish Justice Minister Jose Maria Michavila said criminals had benefited from the freedom of movement provided by European integration and the arrest warrant allowed authorities similar freedom.
"Terrorism, illegal trafficking of human beings ... [are] crimes which grow precisely because of Europe's freedom of movement," he said.
"And yet until the European arrest warrant our prosecutors, judges and police cannot work actively in coordination as one team."
Experts will discuss a range of issues including handing over criminals, communication between countries' judiciaries and extraditing a suspect wanted in several member states.
Their conclusions will be presented to EU justice ministers.