BEIRUT -- Israeli warplanes flew over southern Lebanon Friday, two days after the Jewish state launched an airstrike near Damascus, as Syria's army chief of staff warned against testing his country's capabilities.
Gen. Ali Abdullah Ayoub made his comments Thursday during a visit to some military units in the country. The Al-Baath newspaper, the mouthpiece of President Bashar Assad's ruling party, quoted Ayoub as saying Syria will never change its stance "no matter how much the enemy carries out provocative and hostile acts."
The latest overflights came after officials said Israel launched a rare airstrike Wednesday inside Syria, targeting a convoy carrying anti-aircraft weapons bound for Hezbollah, the powerful Lebanese militant group allied with Syria and Iran.
The general's comments reflected increased tensions between Syria and Israel, which up to now has refrained from actions that could be interpreted as intervention in Syria's civil war.
Israel had no comment on Lebanon's description of the air force flights over the border region. There were no reports of airstrikes. Israeli planes frequently fly over southern Lebanon, and Lebanon often files complaints with the U.N. over the incursions into its airspace.
According to a U.S. official, the Israeli airstrikes Wednesday targeted trucks containing SA-17 anti-aircraft missiles. The trucks were next to the research center the Syrians identified, and the strikes hit both the trucks and the facility.
Advanced anti-aircraft missiles like the SA-17 in the hands of Hezbollah could change the strategic equation, which so far has allowed Israel to send warplanes over Lebanon practically unopposed.
The Syrian military denied that the target of the attack was a weapons convoy. It said low-flying Israeli jets crossed into the country over the Israeli-occupied Golan Heights and bombed a scientific research center. The facility is in the area of Jamraya, northwest of Damascus, about 15 kilometers (10 miles) from the Lebanese.
The air raid raised tension in the already boiling region as a result of Syria's 22-month civil war that has left more than 60,000 people dead, according to the U.N. Many fear Syria's civil war could spill to neighboring countries.
Syria and its close ally Iran threatened retaliation, and Arab nations along with Russia condemned the raid.
In Israel, Foreign Ministry spokesman Yigal Palmor declined to comment on Israeli media reports that its embassies were instructed to be alert for threats after Syria's warnings. Syrian-allied Hezbollah has been accused of staging deadly attacks against Israelis abroad in past years.
At home, Israel positioned an additional "Iron Dome" rocket defense system in northern Israel on Thursday, security officials said, after moving another to the northern city of Haifa earlier this week. The officials spoke on condition of anonymity because they were not authorized to discuss the battery's placement with reporters.
Capt. Eytan Buchman, an Israeli military spokesman, said the military's home front command has not raised its alert level.
The main Syrian opposition criticized the government for not defending the country against the Israeli air raid saying the Syrian army is busy shelling civilian areas in Syria.
"This is not the first time that Israelis warplanes attacked targets inside Syria. Israelis have gotten used to condemnations and strong words that turn out to be nothing more than media bubbles," said a statement issued by the Syrian National Coalition.
"The tragedy is that the regime's, warplanes, helicopters and artilleries were bombarding homes of villagers and turning children into dead bodies and destroying houses over their inhabitants while at the same time, Israeli warplanes were attacking another position," the group said.
"Those who were watching the attacks of warplanes were not able to differentiate between Assad's warplanes and those of the Zionists," the coalition said. "The butchers are many but the victim is one: Syria."
Ayoub, the Syrian military commander, said the "battle with the Zionist enemy continues." He said rebel gunmen fighting against his troops are "tools of the Zionist entity." Israel and Syria have been bitter enemies for six decades.
"We know our capabilities and readiness to use all these capabilities at the suitable time," Ayoub said. "Those who think they can test our armed forces are mistaken."
The uprising against Assad began in March 2011 with pro-reform protests and developed into a civil war. The Syrian government says there is no uprising in Syria but a conspiracy against the country because of its support for anti-Israeli groups.
In Lebanon, the security official said the Israeli fighter planes were seen heading from southern Lebanon toward the eastern Bekaa Valley bordering Syria. He spoke on condition of anonymity in line with regulations.
Butros Wanna, a resident in the southern Lebanese town of Marjayoun, near the border with Israel, said Israeli flights have been intense for the past four days.
"There is something not normal going on. Warplanes are always in the air," said Wanna.