Syria's embattled President Bashar Assad issued a surprise decree Thursday appointing three new ministers, state television said, in a reshuffle following the defection of his former premier.

It said Saad Assalam al-Nayef was appointed health minister, replacing Wael al-Halqi, who became prime minister a week ago after his predecessor defected to join the rebellion.

The United States said Monday it has not ruled out any option to bring about the departure of Syrian President Bashar Assad, following renewed speculation about a possible no-fly zone.

White House spokesman Jay Carney was asked about comments by U.S. Secretary of State Hillary Clinton in Turkey that sparked a new round of questions about a stepped-up Western role in the violence-wracked country.

Tehran will continue to back Syria under President Bashar Assad, which acts as a pillar of an Iranian-led regional alliance, top envoy Saeed Jalili told Assad in Damascus on Tuesday.

"Iran will never allow the resistance axis -- of which Syria is an essential pillar -- to break," said Jalili, a top aide to Iranian supreme leader Ayatollah Ali Khamenei.

U.S. Secretary of Defense Leon Panetta and Jordan's King Abdullah II on Thursday discussed the question of a political transition in "a post-Bashar al-Assad Syria," Pentagon spokesman George Little said.

"They talked not only about how to deal with the current crisis that is being fuelled by the intolerable acts of the regime, but also the prospects for political transition in a post-Bashar al-Assad Syria," Little told reporters.

Troops backed by helicopters pushed an offensive against rebels in Syria's commercial capital Aleppo into a second straight day on Sunday, sparking fierce fighting and sending civilians fleeing.

The opposition Syrian National Council (SNC) accused the government of preparing to carry out "massacres" in the northern city and pleaded for heavy weapons to enable rebels to meet the onslaught.

The United States is stepping up support for the Syrian opposition amid signs events in the 16-month uprising are moving faster on the ground, Secretary of State Hillary Clinton said Tuesday.

After failing to win a U.N. Security Council resolution on Syria after Russia and China imposed their vetoes, the United States is working outside the council to send "a clear message of support for the opposition," she said.

U.S. President Barack Obama warned Syrian leader Bashar Assad on Monday not to make the "tragic mistake" of turning to his stockpile of chemical weapons.

Assad's beleaguered regime had earlier threatened to unleash the weapons if Syria faced international military intervention, although it vowed not to turn them against its own civilians.

Syrian state television broadcast images on Thursday of President Bashar Assad in a meeting with the new defense minister, Fahd al-Freij.

This was the first public sighting of Assad since a bomb attack in Damascus on Wednesday killed three top regime officials, including Freij's predecessor, Daoud Rajha.

Russia said Friday it "categorically" rejected the idea it was siding with Bashar Assad's regime in the Syria conflict, after Moscow's position was slammed at the Friends of Syria meeting in Paris.

"I categorically reject the formulation that Russia supports (President) Bashar Assad's regime in the situation that has developed in Syria," said Deputy Foreign Minister Sergei Ryabkov.

Syrian President Bashar Assad insisted he enjoyed popular support in his own country and said foreign intervention was mainly to blame for the conflict, in an interview published Thursday.

"At the end of the day, we are human too," he told the Turkish daily Cumhuriyet.