BERLIN, March 20 (Xinhua) -- German Chancellor Angela Merkel (CDU) has spoken out in favor of extending German border controls on Tuesday, supporting a call to maintain such measures adopted by Interior Minister and CSU leader Horst Seehofer.

"The chancellor and interior minister have reached an agreement that an extension of controls at the German border is currently necessary," Steffen Seibert, official spokesperson for the chancellery, told the press here.

Earlier, Seehofer had demanded a continuation of border patrols as long as external border management measures established by the European Union (EU) were not sufficiently cohesive and effective. However, a spokesperson for the Interior Ministry noted that the extension would not be indefinite.

EU members and states in the European Economic Area (EEA), which have signed the Schengen agreement, are legally obliged to refrain from internal border controls within the free-travel area that was established in 1995. Exemptions to this rule can only be obtained in exceptional circumstances and on a time-limited basis as defined and granted by the European Commission in Brussels.

Berlin's current provision for border controls in response to the "refugee crisis" expires in May 2018, although the measures have already been extended several times since 2015.

Nevertheless, Boris Pistorius (SPD), the regional interior minister of Lower Saxony, criticized the announcement to expand border checks. "I think the effect of existing stationary controls has been very limited and don't expect that to change as a consequence of their expansion," Pistorius told the newspaper Welt.

German media have widely interpreted Seehofer's proposals in light of looming state elections in Bavaria where the Christian Social Union (CSU) is keen to preserve its long-standing position of power.

Recent opinion polls suggest that the far-right Alternative for Germany (AfD) could secure up to 10 percent of the regional vote, causing the CSU fall short of the absolute legislative majority which it enjoyed continuously for 46 years between 1962 and 2008.