A political solution, Alani said, could prevent Assad "ending up like Gadhafi."
Libyan leader Moammar Gadhafi was captured and killed by rebels on the outskirts of his hometown of Sirte last year, and his corpse was put on public display in a refrigerated locker for several days.
While Ankara maintains that the shells are coming from the regular Syrian army, Paul Salem of the Carnegie Middle East Center, a Beirut-based think tank, did not exclude the possibility of "other sources, a rebel unit, firing across the border, trying to create conditions for Turkey to intervene in Syria."
As the border skirmishes intensified over the weekend and the world began to consider whether Turkey would respond more forcefully, Turkish Foreign Minister Ahmet Davutoglu tried to redirect attention away from the military developments.
On Saturday, Davutoglu said Syrian Vice President Farouk al-Sharaa was a figure "whose hands are not contaminated in blood" and therefore was a possible figure to head a transitional administration.
Abdulbaset Sieda, the head of the Syrian National Council, the main opposition group in exile, said Monday his group is willing to consider Ankara's proposal.
Sieda's comments appear to be a softening of the opposition's stance that it will accept nothing less than the ouster of the Assad regime and the president's inner circle. But this apparent change in heart could be a way for the opposition to appease its Turkish allies rather than a major shift toward a political settlement of the conflict.
Syrian Information Minister Omran al-Zoubi scoffed at Davutoglu's proposal, saying it reflects "obvious political and diplomatic confusion and blundering."
"Turkey isn't the Ottoman Sultanate; the Turkish Foreign Ministry doesn't name custodians in Damascus, Mecca, Cairo and Jerusalem," al-Zoubi said Monday.
Turkey, which shares a 566-mile (911-kilometer) frontier with Syria, nearly went to war with its neighbor over Syrian support for Turkish Kurdish rebels in the 1990s. The relationship improved dramatically since Assad came to power in 2000, and the two countries reached out to build economic ties. But now, Turkey has become one of the most vocal critics of the Assad regime, accusing it of savagery.
The rebels who are trying to bring down Assad have used Turkey as their base, enraging the regime.
Turkey, NATO's biggest Muslim member, became a regional power in the past decade, backed by a growing economy, emerging democratic credentials and historical and cultural links to neighbors. It pursued pragmatic links with authoritarian leaders, but shifted to a pro-democracy position as uprisings swept the Middle East and North Africa.
From the outset of the Syrian crisis, Turkey has tried to position itself as a major player and power-broker — something some observers say was a miscalculation based on overconfidence in Ankara's influence over Damascus. As recently as April, Davutoglu told Parliament that Turkey "will continue to guide the wave of change in the Middle East."
On Monday, Turkish President Abdullah Gul pushed for a Syrian transition, warning that "the worst-case scenario we have all been dreading" is unfolding in Syria and along its borders.
"Sooner rather than later there will be change, a transition," he told reporters in Ankara. "Our only hope is that this happens before more blood is shed, and before Syria self-destructs more than it already has."
AP writers Barbara Surk and Bassem Mroue in Beirut, Albert Aji in Damascus and Suzan Fraser in Ankara, Turkey, contributed to this report.
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