At the same time, other OPEC nations agreed to raise their prices 400%.

Such an asset is seen as one that OPEC nations would want to preserve no matter how deep their differences.

The 13 OPEC nations will meet tonight to hear their decision.

This is not to say that OPEC nations have resolved all their differences.

The 11 OPEC nations have been remarkably effective of late.

Lower production by OPEC nations would begin to push oil prices back up.

The 13 OPEC nations are expected to be sharply divided over whether to raise prices now.

To be sure, the OPEC nations may surprise the market with an agreement to reduce their total output.

OPEC nations agreed to keep the oil production ceiling steady in the spring.

But the attacks raise questions that have left OPEC nations shaken.