Standard & Poor's cut Spain's sovereign debt rating Wednesday by two notches to just above junk level, citing the deepening recession and strains from the country's troubled banks.

S&P cut the rating to BBB- from BBB+, just one level above "speculative" or "junk" grade debt, which could have sent Madrid's borrowing costs skyrocketing to untenable levels.

"The downgrade reflects our view of mounting risks to Spain's public finances, due to rising economic and political pressures," S&P said.

"The deepening economic recession is limiting the Spanish government's policy options," it said, adding that rising joblessness and tighter spending will likely intensify social conflict and tensions between the country's regions and Madrid.

Moreover, S&P expressed doubts that all of the eurozone governments will give their backing to the bloc's effort to recapitalize Spain's banks, leaving more of the burden at least on the Spanish government and forcing its debt burden to balloon.

"Against the backdrop of a deepening economic recession, we believe that the government's resolve will be repeatedly tested by domestic constituencies that are being adversely affected by its policies," S&P said.

"Accordingly, we think the government's room to maneuver to contain the crisis has diminished."

The ratings agency also attached a "negative outlook" to the rating, a warning of a possible further downgrade over the medium term.

Such a downgrade would come, S&P said, if political support for the government's reform agenda weakens, if eurozone support fails to prevent Spain's borrowing costs from jumping above sustainable levels, or if debt tops 100 percent of economic output or debt payments surpass 10 percent of general government revenues. (AFP)