An Israeli military source on Wednesday told Reuters that Israel is bolstering its forces on the once-quiet frontier with Syria where it believes Lebanese Hezbollah militants are preparing for the day when they could fight Israel.The source said the group is gathering intelligence on Israel's deployment on the strategic Golan plateau."It is not at an alarming level now but we understand their intentions," said the source, who asked not to be identified because of the sensitivity of the security and political situation in the area.Hezbollah's leader, Hassan Nasrallah, threatened in May to turn the Golan into a new front against Israel."Since Nasrallah's threat, more (Israeli) army companies have been sent up, more tanks," an Israeli military source at the Booster military outpost on the Golan."Hezbollah has an intelligence presence (in the Golan) that we know of."Booster is about 2 km (1 mile) from a disengagement line set after Israel and Syria fought on the Golan in 1973 and Israeli tanks have just moved back into the position for the first time since then.