ISTANBUL — As diplomats prepared for a weekend effort to revive stalled Syria peace plans, regional tensions swirling around the 16-month-old crisis ticked higher on Thursday as Turkey said it was stationing antiaircraft batteries on their common border following the downing of one of its warplanes.
Turkey’s TRT state broadcaster showed convoys of military trucks carrying antiaircraft guns, a multiple rocket launcher and troops toward several border areas near the southern town of Hatay, where thousands of Syrians have taken refuge from the increasingly bloody insurrection against President Bashar al-Assad’s government
Others were deployed further east near the border settlement of Suruc, joining units close to the frontier post at Mursitpinar, TRT said. Reinforcements were also moved in from the coastal town of Iskenderun.
The deployment came two days after Prime Minister Recep Tayyip Erdogan said Turkey had revised its military rules of engagement toward Syria, warning Mr. Assad that “every military element that approaches the Turkish border from Syria in a manner that constitutes a security risk or danger would be considered as a threat and would be treated as a military target.”
The 550-mile common border has become a critical fault line, used by an increasingly sophisticated network of activists in southern Turkey smuggling supplies into Syria, including weapons, communications gear, field hospitals and even salaries for soldiers who defect.
Almost a week ago, a Turkish warplane was shot down in disputed circumstances off the Syrian coast, with the Turkish government saying the plane was over international waters while officials in Damascus said it was rapidly approaching the Syrian coast when it was hit by shore batteries with a range of less than two miles.
On Wednesday, Syria’s information minister, Omran al-Zoubi, was quoted as telling a private Turkish broadcaster that Syrian antiaircraft gunners might have mistaken the Turkish plane for an Israeli one. “Turkish planes and Israel planes look like each other,” he was quoted as saying by the broadcaster, A Haber. Israel and Turkey both use American-designed warplanes.
Apparently unnerved by the bellicose tones of the authorities in Ankara, Mr. Zoubi said Damascus did not want a crisis with Turkey, a long-standing NATO country that has won support from the alliance in its dispute with Syria over the shooting down of its warplane.
On Wednesday, Kofi Annan, the special Syria representative for the United Nations and the Arab League whose paralyzed peace plan is in danger of collapse, announced he was convening an “action group” meeting of influential countries in Geneva on Saturday in an effort to revive the plan.
But the announcement came only after Mr. Annan had made concessions over which countries would attend. Conspicuously absent from the list of the nations invited were Iran, the strongest regional ally of President Assad, and Saudi Arabia, a prominent supporter of Mr. Assad’s enemies.
In Syria itself, the violence and bloodletting showed no sign of abating.
Gunmen stormed a pro-government television station in a suburb near Damascus on Wednesday, killed seven employees and destroyed its studios with explosives, Syrian officials said, calling the assault a brazen example of atrocities committed by the armed opposition to President Bashar al-Assad.
The attack coincided with a new United Nations report on human rights violations in Syria that mostly castigated the Syrian government.
Rebels disputed the official account of the attack, saying the killers were defectors from Syria’s elite Republican Guard, considered the most loyal core of defenders of Mr. Assad’s inner circle. If the rebel version is confirmed, the attack would constitute a significant breach of security for those close to Mr. Assad, who said on Tuesday that Syria was now in “a state of war.”
The attackers struck against the backdrop of increasingly bold rebel assaults in the Damascus area and an accelerated pace of high-level defections from Mr. Assad’s military. The conflicting accounts of who assaulted the television station, Al Ikhbaria, a satellite broadcaster, reflected the difficulties that outsiders face in determining the true course of events in the Syrian conflict, from which independent reporters and most international relief and monitoring officials are effectively barred.
Those difficulties were illustrated Wednesday in findings by a panel from the United Nations Human Rights Council in Geneva, which is investigating rights violations in Syria but has been blocked from conducting the inquiry inside Syria and has relied heavily on testimony from refugees and defectors. The panel said that it was unable to determine conclusively who was responsible for the May 25 massacre of 108 civilians in Houla, a string of villages in western Syria, but that it “considers that forces loyal to the government may have been responsible for many of the deaths.”
While the investigators accused government forces of committing violations on “an alarming scale” in recent months, they also found that both sides had carried out summary executions. And they said the conflict had escalated significantly despite Mr. Annan’s peace entreaties.
“The situation on the ground has dramatically changed in the last three months as the hostilities by antigovernment armed groups each day take on more clearly the contours of an insurrection,” the investigators said. “As a result of the estimated flow of new weapons and ammunitions, both to the government forces and to the antigovernment armed groups, the situation risks becoming more aggravated in the coming months.”
The attack on Al Ikhbaria began before dawn, when assailants “planted explosive devices in the headquarters of Al Ikhbaria following their ransacking and destroying of the satellite channel studios, including the newsroom studio,” which was destroyed, the official Syrian news agency, SANA, reported.
The news agency referred to the assailants as terrorists, the usual official description of Mr. Assad’s armed opponents.
Al Ikhbaria, which means Syrian Satellite News, is privately owned but strongly supportive of the government. It is in the town of Drousha, about 14 miles south of Damascus.
Col. Malik Kurdi, a spokesman in Turkey for a rebel commander, Riad al-Assad of the Free Syrian Army, said the attack was carried out by a group of Republican Guard members who had decided to defect and had attacked other loyalist guards at the station. There was no way to independently verify the claim from Colonel Kurdi, who was interviewed by telephone from a refugee camp in southern Turkey.
The contradictory versions of events flowed partly from the information war between Mr. Assad’s government and its adversaries.
Anti-Assad activists have proved adept at offering their narrative of the uprising through video clips showing the fighting between government and opposition forces and the bloody aftermath. In recent months, Syrian state media outlets have sought to use similar imagery — sometimes identical — to bolster accusations against the rebels.