Protesters in Cairo march in solidarity with the Syrian opposition movement (Creative Commons).

Moussa Abu Mazouk, Hamas' No. 2, told the AP that the decision to leave Damascus has put Hamas -- the Palestinian Islamist party that governs the Gaza Strip -- at direct odds with both Iran and Syria, two of the party's premier allies.

"Our position on Syria is that we are not with the regime in its security solution, and we respect the will of the people," Abu Marouk said to the AP.

The "policy shift" -- as phrased by Reuters -- is a direct blow to Syrian President Bashar Al-Assad and his remaining list of allies. It also underscores historic religious tensions between Shiite and Sunni Islam in the Middle East.

From Reuters:

In a Middle East split along sectarian lines between Shi'ite and Sunni Islam, the public abandonment of Assad casts immediate questions over Hamas's future ties with its principal backer Iran, which has stuck by its ally Assad, as well as with Iran's fellow Shi'ite allies in Lebanon's Hezbollah movement.

...

Hamas and Hezbollah, confronting Israel on its southwestern and northern borders, have long had a strategic alliance against the Jewish state, despite opposing positions on the sectarian divide. Both have fought wars with Israel in the past six years.

But as the Sunni-Shi'ite split in the Middle East deepens, Hamas appears to have cast its lot with the powerful, Egypt-based Sunni Islamists of the Muslim Brotherhood, whose star has been in the ascendant since the Arab Spring revolts last year.

Reuters also characterized the Hamas-Damascus divorce as "coming for months."

Throughout the nearly year-long conflict in Syria, Hamas has attempted to remain neutral in the civil war, explained Dr. Samir Awwad, a Palestinian politics expert based in the West Bank.

"Aside from the political consequences, Hamas has been afraid to side with the Syrian people in case the regime took out [its displeasure] on the hundreds of thousands of Palestinian refugees in Syria. But Ismali Haniya [Hamas' leader in Gaza] has reasoned that the regime cannot afford now to open a new front against the Palestinians," Awwad told the Telegraph. "Hamas knows that Assad has lost the battle already."

Although Assad's days in power may be fleeting, violence continues to roil Syria, compelling the party to act.

Salah al-Baradweel, a senior Hamas official, addressed thousands of Hamas supporters at a rally in the Khan Younis refugee camp over the weekend, sending what he called a ""a message to the peoples who have not been liberated yet, those free peoples who are still bleeding every day," Reuters reported.

"The hearts of the Palestinian people bleed with every drop of bloodshed in Syria," he told Reuters. "No political considerations will make us turn a blind eye to what is happening on the soil of Syria."

More from the AP here.