Spain's public debt rose to 72.1 percent of gross domestic product in the first quarter of 2012 from 63.6 percent in the same period a year earlier, the Bank of Spain said Friday.

The government expects the public debt to reach 79.8 percent of GDP by the end of the year, a figure that does not include the impact of a eurozone loan of up to 100 billion euros ($126 billion) to ailing Spanish banks.

The ratings agency Moody's warned Wednesday that the loan "will materially worsen the government's debt position" and projected Spain's public deficit would hit 90 percent of GDP this year and continue rising through 2015.

Moody's slashed Spain's credit rating by three notches, from A3 to Baa3, the lowest level of "investment grade" or just above "speculative" or "junk" status. (AFP)