More than 120 people were killed in a spate of ISIS suicide attacks on the Syrian coast Monday, according to activists.
State media said at least 78 people were killed and scores of others were injured in the attacks targeting the cities of Tartus and Jableh.
"We will not be deterred," Syrian Information Minister Omran al-Zoubi said, according to Reuters. "We will use everything we have to fight the terrorists."
Activists put the toll even higher.
The Syrian Observatory for Human Rights said seven suicide bombings hit the two cities, both government strongholds. Russia also has a military presence in Tartus.
At least 73 people died in Jabla and 48 others died in Tartous, according to the activist group. It warned that the death toll was likely to rise.
The ISIS-linked Amaq news agency said the group's fighters were behind the attacks, which targeted civilian gatherings.
The bombers targeted a bus station and the entrance to a hospital in Jableh, according to the official Syrian Arab News Agency (SANA). A bus station also was targeted in Tartus, it added.
Eyewitness Maysam Ahmad, head of the government-run Information Office in Latakia, told NBC News that the scenes were "horrific."
"I saw a lot of blood. The emergency sector at the hospital was completely destroyed. There were pools of blood at the entrance," he said.
Deputy State Department spokesman Mark Toner said the United States condemned the attacks and promised that the U.S.-led coalition would "degrade and defeat Daesh so that it can no longer brutalize those who reject its tormented world view." "Daesh" is an Arabic acronym for ISIS.
Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov consulted by phone after the attacks, Toner said. Kerry urged Lavrov to press the regime of Syrian President Bashar al-Assad to stop airstrikes against opposition forces and civilians in Aleppo and the Damascus suburbs, he said.
Russian President Vladimir Putin, meanwhile, sent condolences to Assad and "reaffirmed" his commitment to cooperate in Syria's fight against terrorism, according to the Kremlin.