BRUSSELS - The European Commission on Monday released its third biannual overview on Schengen governance, in the middle of its efforts to push forward its legislative proposals on strengthened Schengen rules and an EU-based evaluation mechanism.

Covering the period from last November to this April, the latest Schengen "health check" found no serious deficiencies of Schengen rules through spot checks in several countries in terms of police cooperation, air borders, land borders, and visa issuing, among others.

In the six-month period, controls at internal borders was reintroduced once by Norway, on the occasion of the Nobel Peace Prize ceremony last December, during which over 3,000 people were checked and 27 were refused or apprehended, according to the report.

The report also said that from October to December 2012, about 13,600 irregular border crossings were detected, a 52-percent reduction compared to the fourth quarter of 2011.

The Schengen area covers over 400 million people in 26 European countries as well as holders of a Schengen visa. The system was under huge pressure following a sudden influx of migrants from North African countries back in 2011, which then triggered the current reform efforts.

In September 2011, the Commission proposed to strengthen Schengen governance and ensure more efficient border controls with common rules on temporarily reintroducing internal border checks in exceptional cases, as well as a new EU-based evaluation system.

Currently the proposals still need formal endorsement from the Parliament and the Council. The biannual overview has been used as a basis for debates in the two legislative institutions.