FRANKFURT, Germany (AP) -- The European Central Bank has left its key interest rates unchanged at record lows as it assesses the impact on the economy of Britain's vote to leave the European Union.

President Mario Draghi is expected to use his post-decision news conference Thursday to underline the bank's willingness to add to its stimulus programs if the economy takes a serious hit.

Draghi could indicate the bank's readiness to extend its monthly bond purchase stimulus of 80 billion euros ($88 billion) beyond March 2017. The step aims to boost lending and raise inflation.

The ECB's benchmark rate for lending to banks is zero. It has imposed a negative rate on deposits left with it by commercial banks of 0.4 percent, a penalty intended to push them to lend the money.