Israel is mobilising troops to be deployed to the West Bank and Gaza Strip after new alerts that Palestinian militants are planning attacks.
The moves follow Israel's strike on a camp in Syrian territory
Defence Minister Shaul Mofaz has reportedly authorised the rapid call-up of two infantry reserve battalions of 800 troops each.
He has also ordered the reinforcement of defensive positions and extended travel restrictions on Palestinians in the West Bank and Gaza.
The moves come ahead of a meeting of the Israeli cabinet to discuss Israel's next steps following its air strike on what it says was a camp run by Palestinian militants in Syria.
Earlier reports quoted a senior Israeli security source dismissing a threat by Syria's ambassador to Spain on Wednesday that Syria would retaliate militarily if Israel carried out more attacks inside Syria.
Israel was not seeking "an escalation with Syria", the source told Reuters.
The source said Israel would act in self defence in necessary, but not if Damascus "receives our message that it must stop supporting terror".
On Tuesday, Syrian President Bashar al-Assad accused Israel of trying to drag Syria and the rest of the Middle East into a wider conflict through its actions.
But a poll in the Israeli Yediot Aharonot newspaper on Wednesday suggested 65% of 503 people questioned thought the strike was justified.
Israel said it targeted the alleged militant camp in response to a suicide bomb attack on Saturday in the Israeli town of Haifa, which left 19 dead.
Syria denies the target was a training camp and has called on the United Nations to condemn the Israeli action as "military aggression".
Meanwhile, an Israeli minister has said he rejects the new Palestinian government's proposal for a ceasefire.
The Labour minister Zevulon Orlev - from the right wing national Religious Party - said the new Palestinian prime minister, Ahmed Qureia, needed to prove himself through action and not through "pleasant words".
Mr Orlev said that Israel would see how Mr Qureia fights, what he called, the terrorist infrastructure.
Mr Qureia, who was sworn in with a small emergency cabinet on Tuesday, made his fresh appeal for a ceasefire in an interview published by an Israeli newspaper.
He said he was ready to start talks immediately, and asked to be given a chance to prevent a continued deterioration of violence.