BEIRUT, Oct 11 (Reuters) - Lebanon"s Hezbollah chief Sayyed Hassan Nasrallah said on Monday the lead investigator into the disastrous Beirut port blast was biased and politicised, his strongest criticism of the judge since his appointment. "The targeting is clear, you are picking certain officials and certain people, the bias is clear," he said in a televised address, adding that Judge Tarek Bitar would never reach the truth if he continues with the probe. "The current judge is using the blood of the victims to serve political interests," he said, without elaborating. The investigation into the Aug. 4, 2020 explosion, one of the biggest non-nuclear blasts in history, has made little headway amid a campaign against lead investigator Bitar and pushback from powerful Lebanese factions. Wafik Safa, a senior official in the powerful Iran-backed Hezbollah, warned Bitar last month the group would remove him from the inquiry, according to a journalist and a judicial source. read more The justice minister and judiciary are following up on the matter. Bitar"s efforts to question former and current state officials, including the prime minister at the time of the blast, ex-ministers and senior security officials on suspicion of negligence have been repeatedly blocked. Legal complaints have also been filed questioning his impartiality. The probe got frozen for a week earlier this month while one such complaint, that was eventually rejected by the court, was considered. Bitar has scheduled sessions to question former finance minister Ali Hassan Khalil and former public works minister Ghazi Zeiter this week, both allies of Hezbollah, but they are not expected to appear. While Bitar has sought to question several politicians who are allied to the group he has not sought to question any members of Hezbollah itself. The Beirut port blast killed over 200 people, injured thousands and destroyed large swathes of the capital, but more than a year on no top official has been held accountable. Bitar is the second judge whose investigation has been stymied by powerful factions in Lebanon, where a lack of high-level accountability are blamed for systemic corruption, governing gridlock and economic meltdown. His predecessor Fadi Sawan was removed in February by a Lebanese court after a complaint filed against him by a former official he had charged with negligence.