FRANKFURT, Germany (AP) _ The European Central Bank has left its key interest rate unchanged at 1.5 percent as the continent's debt crisis appears to be embroiling Spain and Italy despite efforts by political leaders to contain it.

Market participants are now awaiting ECB President Jean-Claude Trichet's news conference later Thursday, wondering if the ECB will step in and buy Spanish and Italian government bonds to drive down rising borrowing costs that threaten those countries' finances.

The bank has that emergency power, but has not used it for four months and does not like to be seen to support governments, even indirectly. Additionally, Trichet would not necessarily use his press conference to announce them, since the bank makes regular disclosures on any purchases every Monday.

The speculation arises with some European leaders leaving for vacation in August and the head of the European Commission urging faster action. Rising borrowing rates and default fears have already forced Greece, Ireland and Portugal to seek bailout loans and now threaten to pull in Spain and Italy.

Investors and economists will also be looking for clues about whether the bank will carry through on a quarter-point rate hike in October. The move had been widely predicted but is now in doubt because of worries about the economic recovery and the debt crisis.