By Francesco Guarascio and Gabriela Baczynska
BRUSSELS (Reuters) - The European Commission approved on Wednesday extending by six months controls at several frontiers inside the free-travel Schengen area, saying checks were justified by deficiencies in Greece's management of the bloc's external border.
Border controls between Schengen countries are usually not allowed, but in a situation of emergency, such as Europe's migration crisis, checks can be reintroduced for a maximum of two years.
"There is still considerable migratory pressure at our external border, and large numbers of migrants present in Greece," Commission Vice President Frans Timmermans said.
"Therefore, as long as serious deficiencies in (Greece's) border management persist some internal border control measures should be maintained."
The EU executive approved six-month extensions of controls at the German-Austrian border, at Austria's frontiers with Slovenia and Hungary and at Danish, Swedish and Norwegian borders.
"The aim is that, by the end of this year, the Schengen zone will be fully normalized," EU Migration Commissioner Dimitris Avramopoulos told a news conference in Brussels, signaling temporary controls would be lifted as soon as migration flows were under control.
Germany and other Schengen countries introduced emergency border controls last year in an effort to stem chaotic movements of refugees and migrants across Europe after more than 1 million reached the bloc in the last year, mainly via Greece.
The Commission estimated there were still risks that migrants and asylum seekers in Greece could illegally move to other Schengen countries.
Following a deal between the EU and Turkey in March, migrant flows to Greece from Turkey have been reduced considerably, but the Commission said that "the sustainability of the sharp drop in numbers seen over the last weeks still needs to be confirmed".
In explaining the decision to maintain some controls, which was sought by Berlin, Avramopoulos also said the Commission had to take into account concerns about an uptick in new arrivals to Italy.
Austria is building fences at its border with Italy on the Brenner Pass, the major Alpine crossing for heavy goods traffic. Avramopoulos avoided comment, other than to say Italy and Austria were negotiating a solution.
(editing by Philip Blenkinsop; editing by John Stonestreet)