Palestinian militants use a bulldozer to break through the Gaza-Egypt border.

(AP/Hatem Moussa)

In a remarkable act of defiance, Hamas militants stood up to Egyptian President Hosni Mubarak - and won. Again.

After forcing Mubarak to let more than 100,000 Palestinians flood into Egypt over the last three days, Hamas forces refused today to let Mubarak's forces seal up the open border.

When Egyptian forces used water cannons and dogs to prevent Palestinians from coming into Egypt, Hamas responded by bringing in bulldozers to break through the low concrete wall and create a new opening.

One bulldozer crashed through the wall while Egyptian forces in riot gear looked on.

Then, as Palestinians resumed their flow into Egypt, the Egyptian soldiers pulled back.

It is clear that Hamas is not going to stand by and let Egypt seal off Gaza's only opening to the outside world. Hamas appears to be well prepared for a fight.

That puts Mubarak in an untenable situation: He can use force to battle Hamas militants in a fight that would likely be seen around the Arab and Muslim world as a calamity; he can keep the unregulated border open, which would draw the ire of Israel and the US, among others; or he can try to negotiate a deal with Hamas, which would help the Islamist forces regain some political legitimacy.

Hamas leaders are ebullient over events unfolding in Gaza. They have thought this through and were clearly prepared when Mubarak sought to seal the border.

In this ongoing chess game, Hamas right now appears to be out-thinking Mubarak.