The Russian military, sharply escalating its military intervention in Syria, launched 26 medium-range cruise missiles on Wednesday from four Russian warships in the Caspian Sea, while providing air support for a ground offensive by pro-government forces.
Russian officials said the missiles — which traveled more than 900 miles, through Iranian and Iraqi airspace — struck 11 targets in Syria, but they did not specify which groups were hit.
It was not clear whether the missile strike was coordinated with the ground offensive, which was reported by antigovernment activists and insurgents around the central province of Hama, as well as by the television station of Hezbollah, an ally of Syria’s based in Lebanon.
The Kremlin would not confirm that a ground offensive had begun, though a spokeswoman for the Foreign Ministry, Maria V. Zakharova, said that “coordination is taking place with the Syrian Army, that is unequivocal.”
Although the offensive remains in its early stages, it is significant because it is the beginning of a wider, coordinated assault that reveals close collaboration between Syria and its main allies — Hezbollah, Iran and Russia — the official said, speaking on the condition of anonymity because the parties had not detailed the coordination of military strategy.
The assault aims to push back gains early this year by an insurgent coalition, the Army of Conquest, that threated the government-held coastal province of Latakia, crucial territory for the Syrian government, the official said, adding that it was the first time since those setbacks in the spring that government forces had moved “from defense to offense.”
Speaking in tones of new confidence and optimism, the official called the Russian intervention a game-changing development that put to rest any doubts about Russia’s commitment to Syria’s president, Bashar al-Assad, who has managed to cling to power despite a civil war that is now in its fifth year.
The ground offensive aims to push insurgents out of high ground that threatens the rear of Latakia, first in northern Hama Province, where Wednesday’s attacks took place, and later moving north into Idlib Province, according to the official and to diplomats and analysts in the region. Likely targets include Jabal al-Zawiya, a mountainous area that insurgents have held for years, and Jisr al-Shughour, a city in Idlib Province whose capture by insurgents in March was considered an ominous sign for the government.
Russian officials have said since the beginning of their air war that they were targeting Islamic State militants, even when bombs fell on territories held by other insurgent groups that oppose Mr. Assad, including in areas where witnesses reported seeing heavy bombardments on Wednesday.
The strikes have hit the Army of Conquest, an Islamist faction that includes the Nusra Front, Al Qaeda’s Syrian affiliate, as well as more secular groups that often fight alongside, including some that have received American aid. Russia has so far refused to make a distinction between the Army of Conquest and the Islamic State, labeling both groups terrorists.
It was not immediately clear which groups in Syria, if any, were struck by the Russian medium-range missiles.
Russian diplomats, Ms. Zakharova said, have asked the United States to identify armed groups other than units of the Syrian Army that are fighting the Islamic State and that should be avoided in airstrikes, but she said they had received no answer.
“If there are some forces that also have weapons in their hands and are on the ground fighting, as the coalition says, with the Islamic State, and they should not be touched, then wonderful,” Ms. Zakharova said. “Give the list, give the call signs of these people. Tell us where are they located, explain why they shouldn’t be touched. Indeed, this information is not provided.”
Defense Secretary Ashton B. Carter, asked about the new Syrian ground offensive in coordination with Russian airstrikes, lamented “the Assad regime’s use of violence against its own people.”
Mr. Carter added that “to the extent that Russia enables that, that’s the fundamental reason we believe Russia is making a mistake in their actions in Syria.”
He took issue with what he said were suggestions in the news media that the United States was cooperating with Russia on Syria, and said that the only exchanges that the Pentagon and the Russian military could have on Syria at the moment were technical talks on how to steer clear of each other’s way in the skies above the country — so-called deconfliction talks.
“What we will do is continue basic technical discussions on safety procedures for our pilots over Syria,” Mr. Carter said, appearing at a news conference in Rome with Defense Minister Roberta Pinotti of Italy. “That’s it.”
NATO has repeatedly warned Russia — so far, to little effect — that its military intervention will only worsen the situation on the ground. Officials with the Atlantic alliance did not have an immediate response to the cruise missile deployment on Wednesday, but pointed to earlier remarks by its secretary general, Jens Stoltenberg.
“I can confirm that we have seen a substantial buildup of Russian forces in Syria,” Mr. Stoltenberg said at a news conference on Monday. “Air forces, air defenses, but also then ground troops in connection with the air base they have.”
He continued: “We also see increased naval presence of Russian ships, naval capabilities outside Syria or the eastern part of the Mediterranean.”