The main reason for the heightened tensions on the northern front is Iran and Syria's interest to intensify and hasten the arming of Hezbollah. Tehran apparently believes the West's patience is running out quickly and that by the end of the first half of 2013, or by the end of the year, Washington or Jerusalem – or both – will decide on a military strike against Iran's nuclear facilities.
The Iranians want to deter Israel and the Western nations from making such a decision by threats of mass casualties and devastation in the Israeli home front. Tehran plans to realize this threat with the use of Hezbollah and Syria's huge missile and rocket arsenal. Particularly important for the Iranians is Hezbollah's arsenal, which is protected from a ground invasion and is deployed in the heart of a supportive population in south Lebanon.
While Syria has a far larger amount of rockets and missiles, it is difficult to gauge how many of them will actually work when Iran will need them most. Therefore, Iran is looking to beef up Hezbollah's arsenal with as many accurate and devastating advanced long-term rockets as possible - rockets such as the Fateh-110, which are capable of reaching the Tel Aviv metropolitan area and even further south.
http://www.ynetnews.com/articles/0,7340,L-4381060,00.html
