Yemeni troops pressed their seven-week-old offensive against Shiite rebels in the northern mountains Thursday a day after fierce fighting left more than 30 people dead. Yemen also accused aleading figure among separatists in the south of being behind an assassination attempt against a senior security official this week. Heavy gunbattles erupted in Saada province while artillery pounded rebel positions in Amran province further south, commanders said. On Wednesday, 28 rebels were killed in clashes at Uqab, west of Saada town, while four soldiers and five rebels died in fighting in the Harf Sufyan district of Amran, security sources said. Nasser Mansour Hadi, head of Yemen's political security body in the south and brother of the vice president, survived an apparent assassination attempt Wednesday when gunmen opened fire on his motorcade in the town of Zinjibar. Witnesses said two members of his security detail were wounded. “(Hadi) survived a treacherous assassination attempt on the part of subversive elements outside the constitution, system and law belonging to Tarek Al-Fadhli,” an Interior Ministry source said in a statement. “The perpetrators will not escape punishment and security agencies are now hunting them so they face justice.” Fadhli is a tribal leader who switched allegiance to the southerners in 2008. Separatists and security forces exchanged fire Monday at the house of a relative of Fadhli in Zinjibar. In comments to pro-south website Aden News, Fadhli denied any involvement and accused the authorities of staging the attack to sow discord among southern opposition.