A Free Syrian Army fighter inspects his weapon at the Seif El Dawla front in Aleppo August 4, 2013. (Stringer/Reuters)

Syrian rebels launched a major new offensive against forces loyal to President Bashar al-Assad in the country’s northwestern Alawite heartland Sunday, claiming to have overrun a string of villages in the mountains overlooking the coastal port of Latakia.

At least 30 rebel fighters and government loyalists were killed in the fighting, in which the rebels used tanks and heavy artillery to advance to within 12 miles of the Assad family’s mountain home town of Qurdaha in the province of Latakia, according to activists and human rights groups.

The claims could not be independently verified, but videos posted by rebel groups on YouTube showed tanks firing on mountain villages and rebel groups raising their flags over captured government positions in villages belonging to members of Assad’s minority Alawite sect. The Latakia Coordination Committee said scores of Alawites had fled from the countryside into the city.

The push in Latakia comes as the rebels show signs that they are starting to recover from a string of recent setbacks that had triggered concerns among their regional allies that Assad’s regime may be poised to crush the 21 / 2-year-old revolt. Rebel commanders and opposition leaders say the concerns appear to have spurred fresh supplies of weapons to the rebels in recent weeks, though it is unclear who is supplying them.

The scale of the offensive, which appeared to be the biggest yet in the Assad family’s heartland, will come as a blow to the recent confidence displayed by the regime, said Charles Lister of IHS Jane’s Terrorism and Insurgency Center.

Jihadist groups, including the al-Qaeda-affiliated Islamic State of Iraq, appear to have taken the lead, with as many as 1,000 fighters, many of them foreigners, from more than 40 rebel units taking part, he said. Tunisians, Libyans, Saudis and Jordanians were among those reported killed in the initial attacks, he added.

Omar Abdulrahman, an activist living in Latakia, said the streets echoed the sound of sirens throughout the day as ambulances ferried wounded soldiers from the front lines, contributing to what he called “a hysterical mood” among residents of the mostly pro-government city.

In a further sign that the regime is facing difficulties, Assad issued a decree Sunday prohibiting commercial transactions in foreign currencies, signaling another effort to prop up the collapsing Syrian pound. The currency, which traded at 47 to the U.S. dollar on the eve of the 2011 uprising against Assad’s rule, has plunged in recent weeks to a low of more than 300 to the dollar on the black market.

But the government remains confident that it can count on the support of its ally Iran, which has sent arms as well as financial aid to sustain the Assad regime. The official Syrian Arab News Agency trumpeted comments by new Iranian President Hassan Rouhani at his inauguration indicating that he intended to sustain Iranian support for Syria.

“President Rohani stressed that no power in the world can destabilize or undermine the deep-rooted, historic and strategic relations between the two friendly peoples and countries which are based on understanding, common destiny and fulfilling the aspirations of the two peoples,” the news agency said.