BERLIN - German chancellor and Christian Democratic Union (CDU) leader Angela Merkel has expressed doubts on Tuesday that a comprehensive agreement on asylum policy will be reached between member states at an upcoming European Union (EU) summit.

Speaking to press in Berlin after a meeting with the visiting Spanish Prime Minister Pedro Sanchez, Merkel highlighted that two out of seven guidelines for a proposed new EU approach remained to be clarified.

The establishment of a uniform framework for asylum procedures and an overhaul of the so-called "Dublin IV" system which determines national responsibilities for refugees arriving in the Schengen free-travel area, according to Merkel, were "requiring a little bit more time."

In light of the elusiveness of a consensus in the EU on asylum policy, the veteran stateswoman reiterated an appeal to allow individual member states to negotiate bilateral agreements with transit countries and refugees' countries of origin which could then become applicable to the wider bloc.

Spain has already voiced its support for Berlin's position and said that it would support Merkel's efforts to find an efficient and united EU approach at the Brussels summit on Thursday and Friday.

The ruling CDU and its Christian Social Union (CSU) sister party in the German federal government are currently locked in a widely-publicized political impasse over the question of whether or not to turn back asylum seekers at Germany's borders who were already registered in another Schengen area country.

As outlined in his "migration master plan", interior minister and CSU leader Horst Seehofer wants to refuse asylum seekers access to German territory if they have already formally entered the Schengen zone via another country. By contrast, Merkel has warned of a resulting domino effect as Germany's neighbors rush to shutter their internal Schengen borders and is calling for a joint European approach.

Seehofer has insisted that "nobody would be happier" than himself if a European solution in the asylum conflict was achieved. Yet in spite of the threat of being sacked from cabinet and triggering the collapse of the German federal government, the CSU leader has warned that he will press ahead unilaterally with his "migration master plan" unless Merkel secures a binding and comprehensive agreement from other EU member states at the Brussels summit.