Earlier on Monday, Portugal's main court rejected the austerity measures which are central to country's financial aid pressure, highlighting tensions in the euro zone. The Portuguese benchmark index underperformed, closing 1.40 percent down on the day.
"Fiscal austerity in Portugal is failing," Nick Spiro, head of Spiro Sovereign Strategy, told CNBC. "Portugal's 2011 bailout program went off track some time ago. If it were not for the troika's leniency and the dramatic rally in Portuguese debt, the program would have already failed by now."
(Read More: Portugal Fires Warning Shot for Austerity in Europe)
In addition, U.S.Treasury Secretary Jack Lew is in Europe for economic discussions with the region's officials and leaders. Lew is scheduled to travel to Frankfurt this evening where he will meet with European Central Bank President Mario Draghi.