According to a Commission communiqué, its experts had meetings with the relevant Danish authorities in Copenhagen and visited the Danish-German and Danish-Swedish borders on 14 July.
The visit was prompted by the Danish government's decision to reintroduce border controls at its ports and airports, as well as along its only land border with Germany and its bridge to Sweden (see 'Background').
"In a first assessment the experts reported that they were unable to get sufficient justifications from the Danish side for the intensification of the controls at the internal borders," the Commission states.
In particular, according to the experts, the risk assessment required to justify the controls had not been sufficient and there had not been clear instructions to border control officers on how to carry out controls.
"There also does not seem to be a structured reporting mechanism about the number of controls and the results of the intensified border checks," the statement says.
EU Home Affairs Commissioner Cecilia Malmström, who coordinates the work of the European Commission's services involved, expressed concern about the situation.
"Unfortunately, the mission did not enable us to get adequate answers to our questions. There are persistent concerns about the compatibility of Denmark's strengthened internal control measures with the freedoms provided under the EU Treaty, including the Schengen acquis," she is quoted as saying.
Malmström said that her services had already sent a letter to the Danish authorities to get further clarifications and further visits were excluded.
"The Commission will not hesitate to use all tools at its disposal to guarantee free movement of goods, services and persons and the full respect of EU legislation," Malmström warns.
Denmark will take over the rotating EU presidency as from 1 January 2012.
