BRUSSELS — NATO leaders Thursday condemned Russia’s military intervention in Syria and vowed to sharpen their eastern defenses from the Baltics to Turkey, but they stopped short of taking concrete action to parry Moscow’s moves in the Middle East.
At a meeting of NATO defense ministers at its headquarters here, Secretary General Jens Stoltenberg decried a “troubling escalation” by Russian forces in Syria and the use of “some of their most modern weapons” near NATO’s borders. At the same time, alliance leaders appeared to have scant appetite for a confrontation with their longtime adversary and limited their response to minor or symbolic military countermeasures.
Meanwhile, Russia intensified its attacks on Syrian rebels. The Russian Defense Ministry said its warships in the Caspian Sea fired four more cruise missiles at Islamic State targets from nearly 1,000 miles away, a potent exhibition of Moscow’s firepower.
Also Thursday, Russian warplanes continued to back Syrian troops and allied militias in a campaign to reclaim territory in western Syria from various rebel factions opposing Moscow’s ally, Syrian President Bashar al-Assad. The targeted groups include various Western-backed fighters.
In an echo of the U.S. government’s response to another Russian military intervention last year, when Moscow helped spark a civil war in Ukraine and annexed Crimea, U.S. Defense Secretary Ashton B. Carter warned Russia that it risked being shunned by the rest of the world but suggested that external pressure could go only so far.
“Russia has continued to wrap itself in a shroud of isolation, and only the Kremlin can decide to change that,” Carter told reporters in Brussels. “It remains our hope that Russia will see that tethering itself to a sinking ship is a losing strategy.”
He added: “Russia has the opportunity to change course and do the right thing. I don’t know if they will.”
Carter predicted that Moscow’s intervention in Syria would backfire strategically but also in loss of life, saying that he expected Russian casualties to mount. “This will have consequences for Russia itself,” he said.
Shortly after Carter spoke, reports surfaced that Russian missile attacks had gone badly awry.
A senior U.S. defense official who spoke on the condition of anonymity said the Pentagon had tracked Russian cruise missiles, fired from ships in the Caspian Sea, that had crashed in Iranian territory. It was unclear whether there were any casualties. Officials in Moscow and Tehran did not immediately respond to the reports.
Backed by Russia, the Syrian government expanded its offensive Thursday from Hama and Idlib provinces in the northwest toward the Mediterranean coast near Latakia, a stronghold of Assad’s Alawite sect, and the Ghab plain.
The Free Syrian Army, which is backed by the United States and its allies, posted several videos showing rebels striking Syrian regime tanks with U.S.-made antitank missiles.
Rebels and activists also uploaded images of what they said were explosions from Russian airstrikes. It was unclear how many people were killed in the fighting.
Activists also reported that Western-backed rebels shot down two helicopters in Hama province, although it was unclear whether the downed aircraft were Russian or Syrian. The reports could not be independently verified.
In a televised speech, Gen. Ali Ayoub, the Syrian army chief of staff, credited the Russian strikes with enabling government forces to expand ground operations against insurgents.
“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, according to the Associated Press.
As the fighting continued, NATO leaders sought to reassure Turkey that the alliance would take any necessary steps to help defend Turkish territory from a Syrian spillover. Russian fighter jets have violated Turkish airspace on at least two occasions in the past week, prompting protests from Ankara and Brussels.
“NATO is able and ready to defend all allies, including Turkey, against any threat,” Stoltenberg, the NATO secretary general, said from alliance headquarters as defense ministers gathered.
Stoltenberg told reporters that Turkey had not requested additional troops or weapons from NATO, though he said the alliance was “in constant dialogue” with Ankara about the Russian military presence near its borders.
“You have to remember that Turkey is a strong ally,” he said, noting that Turkey has the second-largest army in NATO. “The important thing for Turkey is that they know they are a part of NATO, that the security guarantees are 100 percent rock solid.”
NATO leaders said they were revisiting previously laid plans to withdraw Patriot missile batteries that have been deployed to Turkey for the past two years.
The alliance originally stationed three batteries in Turkey to deter cross-border rocket and missile attacks from the Syrian government. Two of the batteries — manned by Germany and the United States — are scheduled to be removed this fall, leaving a single unit operated by the Spanish military.
The Patriots are designed to intercept land-based missiles or rockets, and military officials said they would be of little use against Russian warplanes. But some NATO officials said they were sensitive to Turkish concerns that a withdrawal would send the wrong message to Russia and were examining whether other countries could fill the gap by deploying additional batteries.
NATO also finalized long-standing plans to expand a joint-response force to 40,000 troops, double the current number. It also said it would establish small regional headquarters in Hungary and Slovakia, adding to six other new headquarters operations in Eastern European countries.
Those plans have accelerated since Russia seized control of Crimea and began supporting separatist rebels in eastern Ukraine last year.
“NATO has to respond when we see a more assertive Russia behaving the way it has behaved,” Stoltenberg said.
Cunningham reported from Beirut. Thomas Gibbons-Neff in Washington contributed to this report.