INDICATIONS of increased Russian involvement in Syria in support of president Bashar al-Assad are prompting a reassessment in Israel about how to handle fallout from the conflict without risking a clash with Moscow.

Since the Syrian civil war began in 2011, Israel has occasionally fired across the Golan Heights in response to spillover shelling or bombed advanced arms it suspected were to be transferred to Assad’s Lebanese guerrilla allies, Hezbollah.

US and regional reports that Moscow’s diplomatic and logistical support for Assad is shifting into major military backing has raised the prospect of Israel and Russia accidentally coming to blows.

“There could be ramifications for us, certainly,” Ram Ben-Barak, director-general of Israel’s Intelligence Ministry, said when asked if Russian intervention in Syria might necessitate new Israeli rules of engagement.

He was speaking at a security conference organised by the Herzliya Interdisciplinary Center, where Russian policy in Syria was described both as an effort to shore up Assad and mobilise with other world powers in suppressing Daesh insurgents.

“We have been informed the Russians are entering into active intervention, the Americans are attacking ... The West and now, in fact, the Russians and the whole world are trying to unite against them (Daesh),” Amos Gilad, senior adviser to Israeli defence minister Moshe Yaalon, said in a speech.

In separate remarks to Reuters, Gilad said it was too early to know how extensive Moscow’s military involvement would be.

“I don’t know, because the scale is not yet clear. They haven’t started working,” Gilad said.

Asked if Israel was communicating with Russia in a bid to head off any unintended confrontations between their forces, he said only: “There are ways. They are not our enemies today.”

In Moscow, the foreign ministry spokeswoman said she had no information about any communication between Israel and Russia.

Israel has sought to stay out of the Syrian civil war, seeing enemies on all sides. It says it intervenes militarily only when fired upon from Syria or to prevent Hezbollah operatives reinforcing Assad.

Past Israeli strikes killed Syrian troops as well as Hezbollah fighters, according to both countries and the guerrilla group.

Moscow has reaffirmed its military backing for Damascus but said it was premature to talk about Russian participation in military operations in Syria.

US authorities have detected “worrisome preparatory steps”, including transport of prefabricated houses for hundreds of people to a Syrian airfield, that could signal Russia is readying for deployment of heavy military assets, a senior US official said last week.

Amos Yadlin, an Israeli air force ex-general and prime minister Benjamin Netanyahu’s former military intelligence chief, said Israel and Russia were unlikely to find themselves pitted against each other in Syria as they had different areas of interest.

“I don’t think there is any reason for the sides to collide, as we are not fighting the same enemy,” said Yadlin, now director of Tel Aviv University’s Institute for National Security Studies.

He predicted Russian forces would avoid the Golan, near Israel’s northern front, and Israel would think twice about carrying out air strikes where Russians might be harmed.

“My assumption is that we don’t attack any site on the ground in Syria unless we have an excellent picture of who is or isn’t there,” Yadlin said.