JERUSALEM, March 13 (Reuters) - Israel has launched a new phase of its assault on Iran, targeting checkpoints manned by the Islamic Revolutionary Guard Corps (IRGC) based on tip-offs from informants on the ground, a source briefed on Israel's military strategy told Reuters. On Thursday, Israel's military said it had struck checkpoints in Tehran operated by the Basij, a part-time paramilitary force under IRGC control that is often used to quell protests inside Iran. The source, who spoke on condition of anonymity because they were not authorised to speak publicly, said informants on the ground in Tehran had passed intelligence to Israel on the locations of three checkpoints that were struck in the past three days. The source was not able to confirm whether these included the Basij positions mentioned by the military. Israel targets Iranian checkpoints using tip-offs from informants, source says