BEIRUT, Lebanon -- Turkey fired artillery into Syria for a fourth consecutive day on Saturday after another Syrian mortar shell landed on the Turkish side of the increasingly tense border.
The exchanges -- and Turkey's recent warnings to Syria that it would defend itself -- have raised fears of regional conflict. While stray shells and bullets from the Syrian conflict have often landed in Lebanon and Turkey, for the first time a Syrian mortar shell killed five Turkish civilians on Wednesday, prompting Turkey's response.
Both Syria and Turkey on Saturday denied that Syria had pulled its forces back six miles from the border to avoid provoking Turkey, as the Turkish news media had reported a day earlier. Rebels have long wanted a buffer zone along the border.
Rebel activity was heightened along the border area in Syria's Idlib Province on Saturday, according to antigovernment activists who said rebels had seized the Syrian village of Khirbet al-Jouz, not far from where the mortar shell landed in a field in the Turkish village of Guvecci. Rebels also claimed to have seized a checkpoint at Darkush, also in the border region.
It was unclear whether rebels were taking advantage of a moment of Syrian restraint or hesitation, or simply building on gains in the area, where government forces are absent from large swaths of territory.
In another province bordering Turkey, Latakia, unusually intense fighting was reported. Latakia, the home province of the Assad family's Alawite clan, has remained relatively calm. Activists said 10 insurgents were killed trying to seize a military outpost.
Anxiety over the conflict spilling into Lebanon erupted again on Saturday as unnamed Lebanese intelligence sources told local news media they had evidence that a prominent media adviser to President Bashar al-Assad of Syria was involved in a plot to stir sectarian violence in Lebanon.
The adviser, Buthaina al-Shabaan, was frequently a spokeswoman for the government during Mr. Assad's early years in office, when he was portraying himself as a reformist. It was impossible to immediately confirm the accusations, and Syria made no statements on the matter.
The Daily Star and MTV television reported that intelligence officials say they have evidence from phone records that Ms. Shabaan was involved in a plot with Michel Samaha, a former Lebanese government minister who was arrested in August. Mr. Samaha was accused of transporting explosives to be used to assassinate Lebanese political figures in what authorities in Lebanon said was a Syrian scheme to instigate sectarian conflict in Lebanon.
Continued heavy shelling was reported on Saturday morning by antigovernment activists in the city and province of Homs. Scores of people were killed in the town of Houla in Homs Province, sending residents fleeing, according to the Local Coordinating Committees, a network of activists inside Syria, and the Syrian Observatory for Human Rights. The government news agency SANA has said in recent days that security forces were carrying out operations in Homs to combat terrorists, its term for the armed opposition, and have recovered many weapons and explosives there.
Shelling was also reported in near Damascus and in the southern province of Dara'a. The government has struggled to maintain control in those areas, even after repeatedly shelling them and declaring order restored.
Hania Mourtada contributed reporting from Beirut.
This article originally appeared in The New York Times.