U.S. President Barack Obama said he was "appalled" by Syria's crackdown on Sunday which activists say killed nearly 140 people and vowed to step up pressure on President Bashar al-Assad's regime.

In a statement, Obama saluted demonstrators who have taken to the streets as "courageous" and said Syria "will be a better place when a democratic transition goes forward."

Syrian President Bashar al-Assad held talks Tuesday in Damascus with Lebanon’s Energy and Water Minister Jebran Bassil on the situations in Lebanon following the formation of the new government and the Syrian-Lebanese relations, Syria’s official news agency SANA reported.

Talks also dealt with the situation in Syria and the region, SANA added.

Israeli President Shimon Peres on Tuesday called on Syrian leader Bashar al-Assad to resign, directing his message to the Arab world in his first news conference for Arab media.

Peres also voiced respect for Syrian demonstrators who he said "are fighting for peace and who want to live like human beings."

Syrian President Bashar al-Assad has replaced the governor of Deir Ezzor, the state news agency SANA reported on Sunday two days after massive anti-regime protests in the eastern oil hub.

Assad issued a decree appointing Samir Othman al-Sheikh to replace Hussein Arnoos as governor, the agency said.

Progressive Socialist Party leader MP Walid Jumblat noted on Monday that the developments in Syria demonstrated that it is impossible to carry on with the security approach over the country’s anti-regime protests.

He said in his weekly editorial in the PSP-affiliated al-Anbaa magazine: “A new approach should be adopted through resorting to dialogue.”

Hundreds of Syrian dissidents debated strategies to oust Bashar Assad's regime Saturday in Istanbul as U.S. Secretary of State Hillary Clinton called for a halt to the "brutal" repression of protests.

A simultaneous gathering scheduled to take place in Damascus was cancelled after at least 28 civilians were killed, including 16 in the capital, in demonstrations on Friday, activists said.

U.S. Secretary of State Hillary Clinton on Friday said Syria cannot return to the way it was before unprecedented anti-regime protests, but how the situation would evolve remained unclear.

"We have said that Syria can't go back to the way it was before," Clinton said on the sidelines of a meeting of the Libyan contact group in Istanbul.

Arab League Secretary-General Nabil al-Arabi said Wednesday that Washington overstepped its bounds by saying Syrian President Bashar al-Assad had lost the legitimacy to lead his country.

Following talks with the Syrian president in Damascus, Arabi said Assad assured him that "Syria has entered a new era and is now moving on the road of a genuine reform."

An explosion hit a gas pipeline in northeastern Syria late Tuesday in the first attack on the country's energy infrastructure since protests erupted in March, a human rights activist said.

"The explosion hit the gas pipeline last night at 11 pm (20:00 GMT) in al-Tayyaneh northeast of the town of Mayadin," the director of the London-based Syrian Observatory for Human Rights, Rami Abdel Rahman, told Agence France Presse in Nicosia.

Syrian President Bashar al-Assad on Sunday issued a decree naming Anas Naim as the new governor of the central city of Hama after firing Ahmed Khaled Abdul Aziz from the post on July 2, a day after huge anti-regime protests labeled the largest ever.

On July 2 some 500,000 people took to the streets, without security forces intervening, activists said, calling it the single largest demonstration of its kind since the pro-democracy movement erupted on March 15.