BEIRUT — Members of a US commando force carried out a ground operation in eastern Syria aimed at capturing leaders of the Islamic State group, US officials said Monday.
The two-hour raid took place Sunday in a small town near the city of Deir al-Zour, deep in the heart of Islamic State territory, US officials said. At least 25 militants were killed, according to the Syrian Observatory for Human Rights, a monitoring group.
The troops, who landed with helicopters, spent about 90 minutes in the area, then left carrying Islamic State captives and bodies, according to witnesses quoted by the website Deir al-Zour 24, which monitors Islamic State activity in that province.
A US official said the Americans intercepted a vehicle thought to be carrying senior Islamic State members but declined to confirm that militants had been killed.
The official, who spoke on the condition of anonymity, said there were no American casualties.
The US-led coalition has in recent months targeted and killed a string of senior Islamic State officials with drone strikes, but ground raids aimed at capturing leaders are rare.
Sunday’s raid appeared to be an operation by the Expeditionary Task Force, a team of Special Operations forces based in Iraq that is charged with hunting down Islamic State leaders.
In a separate development Monday, Syrian President Bashar Assad said in an interview that he was prepared ‘‘to negotiate everything’’ at planned talks later this month in Kazakhstan, seeking to cast himself as a peacemaker after his forces recaptured Aleppo last month.
The talks, brokered by Ankara and Moscow, are scheduled to begin Jan. 23, but they are still in doubt as Syrian opposition groups have yet to confirm their participation.
Speaking to French reporters at his Damascus palace, Assad defended his troops’ deadly bombardment of eastern Aleppo, saying the alternative would have been to leave the city’s civilians at the mercy of ‘‘terrorists’’ — a term the government uses for all rebels, the Associated Press reported.
Assad questioned the credibility of Syrian opposition groups backed by the West and Saudi Arabia, which make up the bulk of the armed and political opposition to his rule.
‘‘There’s no limit to negotiations,’’ Assad said, in remarks carried by Syrian state media. ‘‘But who is going to be there from the other side, we don’t know yet . . . The viability of the conference depends on that.’’
Past Syrian peace talks have run aground on the question of Assad’s future and whether he is to continue as president, with the opposition insisting his departure is a precondition for a permanent end to hostilities.
Assad said the matter could be resolved only through a constitutional referendum.
Colonel John Dorrian, spokesman for the US-led coalition, said Sunday’s commando raid was part of ongoing efforts to track down ISIS leaders.
He said the coalition “will continue to pursue ISIL leaders wherever they are to ensure the security and stability of the region and our homelands,’’ using another acronym for the Islamic State.
