Clashes intensified Thursday between Syrian troops and insurgents in central and northwestern Syria, part of what a top general called a "wide-ranging" offensive aided by Russian airstrikes and apparently aimed at clearing positions near government strongholds on the coast.
US defense officials said as many as four of the 26 long-range cruise missiles that Russia said Wednesday it fired at Syria landed instead in Iran, but it was unclear if they caused any significant damage. Russia said all of its missiles fired from warships hit their targets.
Russia's involvement in Syria, which began with airstrikes Sept. 30 and escalated Wednesday with cruise missiles, "raises serious concerns," NATO Secretary-General Jens Stoltenberg said after a meeting of the alliance's defense ministers in Brussels.
Russia says its air campaign in Syria is aimed against militants of the Islamic State and Al Qaeda-linked groups, but the West accuses it of intervening to support President Bashar against even moderate rebels in the civil war.
The Syrian government's multi-pronged offensive began Wednesday, and state-run media said it seized several villages in central Syria, with fighting continuing Thursday. The government media and activists reported heavy fighting in Sahl al-Ghab, a vital plain bordering Assad's stronghold of Latakia on the Mediterranean.
The plain also lies between Hama and Idlib, the northwestern provinces seized from government troops in September. Insurgents have been advancing there since summer, threatening the coastal region where Assad's family and the Alawite minority, an offshoot of Shiite Islam, are concentrated.
The Islamic State — also known as ISIS, ISIL or Daesh — has strongholds in Raqqa and Aleppo provinces, while Syria's al-Qaida affiliate, the Nusra Front, has a strong presence in Idlib.
Gen. Ali Ayoub, the Syrian army's chief of staff, said Russia's airstrikes had weakened the Islamic State fighters and other insurgents so that his troops could keep up the initiative.
"Today, the Syrian Arab armed forces began a wide-ranging attack with the aim of eliminating the terrorist groups and liberating the areas and towns that suffered from their scourge and crimes," Ayoub said in rare televised remarks. The government uses the term "terrorists" to refer to all armed opposition groups in Syria.
Russia said its warplanes flew 22 sorties and carried out 11 airstrikes on IS training facilities in Hama and Raqqa provinces.
The Russian Defense Ministry also said its aircraft destroyed firing positions in rural Hama, where fighting has raged, and struck militants' underground facilities in rural Latakia with concrete-piercing bombs.
Syrian TV showed government troops loading and firing artillery as helicopters flew over rural Hama and Idlib. It also showed tanks and airstrikes. The state run SANA news agency said joint Syrian-Russian airstrikes hit 27 targets belonging to Nusra Front.
Heavy fighting was concentrated in the rural parts of Idlib, Hama and Latakia provinces — areas of operation for an array of insurgent groups that includes the Nusra Front. The Western-backed Free Syrian Army also has a presence in the area, while the Islamic State has a limited presence in western Hama, where activists reported no fighting or airstrikes.
The Britain-based Syrian Observatory for Human Rights and other activists said a military helicopter was downed in Kfar Nabouda, in northern Hama. Local media said the helicopter belonged to the Syrian government. The Observatory said Russian jets bombed areas near the site.
The ultraconservative militant group Ahar al-Sham, part of the coalition known as the Army of Conquest that controls Idlib, posted video showing it launching Grad rockets at government troops. The troops advanced on a village previously controlled by the rebels.
Syrian Deputy Foreign Minister Faisal Mekdad told state TV the Free Syrian Army, an umbrella group for dozens of Western-backed rebel groups, is no different from other militants.
"There is no difference between Nusra Front, Daesh and the Free Syrian Army — if it still exists," he said. "They started (the armed opposition) and taught Daesh and Nusra all these crimes committed against Syria now."
The Observatory, which has a network of activists across Syria, said the Russian airstrikes in Idlib killed at least seven civilians Wednesday.
The Violations Documentation Center, a Syrian rights group, said at least 43 civilians, including nine children and seven women, were killed Sept. 30, the first day of Russia's airstrikes, in central Homs province. The group, relying on witnesses and video, said the strikes hit predominantly civilian areas in three villages and towns, including homes and a bread distribution center.
The Russians maintain no civilians were killed.
The group said it documented the use of at least two vacuum bombs — thermobaric weapons "which are entirely indiscriminate in nature and impossible to evade, even when taking shelter." The group alleged the attacks constituted a "grave violation of international humanitarian law and, as a result, a war crime."
Syria's conflict, which began as an uprising against Assad in March 2011 but became a full-blown civil war after a fierce government crackdown, has killed 250,000 people, according to UN figures.
Russia said Wednesday it launched 26 cruise missiles from warships in the Caspian Sea that hit targets in the Syrian provinces in the north and northwest, taking flight paths over Iran and Iraq.
As many as four landed instead in Iran, according to three US officials, speaking on condition of anonymity because they were not authorized to discuss the matter publicly. One of the officials said the number of missiles that went off course was four.
Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said Thursday that "all rockets fired from ships found their targets."
Iranian government officials could not immediately be reached for comment, but the semi-official Fars news agency said Western news reports of missiles going astray amounted to US "psychological warfare" against Russia's intervention in Syria. A report Wednesday by Fars quoted Iraj Saghafi, acting governor of Takab in northwestern Iran, as saying an explosion heard in the region was "possibly related to work in a nearby rock quarry."
Russia's intervention has alarmed the West and its NATO allies, particularly Turkey, which shares a long border with Syria and has been a leading backer of the Syrian rebels.
On Thursday, the alliance signaled its readiness to defend Turkey if needed from any threats from Moscow. Russian jets twice violated Turkish airspace over the weekend.
"NATO is able and ready to defend all allies, including Turkey, against any threat," Stoltenberg said.
US Defense Secretary Ash Carter said Moscow has insisted it is striking facilities of the Islamic State militant group, but that so far this hasn't matched up with the targets Russia is blasting from the air.
"They have initiated a joint ground offensive with the Syrian regime, shattering the facade that they're there to fight ISIL," Carter said.
Russia's support for Assad "will have consequences for Russia itself," he said, adding: "I also expect that in coming days the Russians will begin to suffer casualties in Syria."
Turkish President Recep Tayyip Erdogan warned that Moscow's military action in Syria endangered trade ties with his country, saying Ankara could look elsewhere for gas supplies and cancel the construction of its first nuclear power plant, which is being built by Russia. Russia supplies 60 percent of Turkey's gas needs.
President Vladimir Putin was informed of Erdogan's remarks but hoped they would not affect relations between the two countries, said Kremlin spokesman Dmitry Peskov.
"We sincerely hope that these relations will continue to expand according to the plans mapped out by Putin and Erdogan because this cooperation is genuinely mutually beneficial and is in the interests of both our countries," Peskov said.