The death toll from an airstrike attributed to Israel Sunday rose to at least 42 Syrian soldiers, according to the Britain-based opposition activist group Syrian Observatory for Human Rights.
The group said Monday that the death toll was based on information from Syrian military hospital sources. The Syrian government has not released any numbers related to the airstrike.
Israeli and US officials anonymously told the Associated Press that Israel had carried out three airstrikes in Syria so far this year, the most recent ones on Friday and Sunday.
Israeli newspaper Ha'aretz said reports suggested the strikes were on shipments of Iranian Fateh-1oo missiles, which were en route to Lebanon's militant group Hezbollah.
Israel has yet to confirm the strike, reports GlobalPost's Noga Tarnopolsky in Jerusalem.
"The Israeli authorities have had no comment on any military activity in Syria," she said.
Asked by GlobalPost to comment on Sunday's strike, Israel's Foreign Ministry spokesman Yigal Palmor quoted philosopher Ludwig Wittgestein: "'Whereof one cannot speak, thereof one must remain silent.'"
Yair Golan, the commanding general of Israeli forces on the Syrian and Lebanese borders, told reporters, "There are no winds of war."
"Do you see tension? There is no tension. Do I look tense to you?" he said, according to Reuters. A confidant of Israeli Prime Minister Benjamin Netanyahu, Tzachi Hanegbi, told Israel Radio that Israel sought to avoid increasing tensions with Syria "by making clear that if there is activity, it is only against Hezbollah, not against the Syrian regime."
Netanyahu arrived in Shanghai for a visit on Monday as China leveled criticism at the airstrikes.
"We are opposed to the use of force and believe that the sovereignty of any country should be respected," foreign ministry spokeswoman Hua Chunying said at a press briefing. She added that China urged all sides to "exercise restraint and refrain from actions that may escalate tensions."
Netanyahu, who is on a five-day visit to China, has already held business meetings in Shanghai. He is due to visit Beijing on Wednesday.
Russia also voiced concern on Monday over the airstrikes. "We are looking into and analyzing all the circumstances surrounding the especially concerning reports of the May 3 and May 5 Israeli airstrikes," said a statement from the foreign ministry.
"A further escalation of the armed conflict severely raises the risk of creating centers of tension in Lebanon as well as in Syria, and also destabilizing the still relatively stable situation in the region of the Israeli-Lebanese border," it added.
Lebanon on Monday called on the UN Security Council to condemn violations of its air space by Israel, in connection to the airstrikes. In a letter obtained by Reuters, Lebanon urged the council to "compel Israel to halt its violations of Lebanon's sovereignty by air, sea and land, and carry out all its obligations in accordance with resolution 1701."
The letter read, "The Israeli Air Force continues to violate Lebanese airspace and in the previous days intensified its circuits above Lebanon. This constitutes a disgraceful violation of [Lebanon's] sovereignty."
More from GlobalPost: The world reacts to Israel's continued airstrikes on Syria
GlobalPost senior correspondent Noga Tarnopolsky contributed reporting from Jerusalem.