(Updates with Abbas, Haniyeh meeting over, no deal yet) By Nidal al-Mughrabi GAZA, March 13 (Reuters) - Hamas vowed to avenge the killing of a leader in its armed wing on Tuesday in Gaza in renewed violence that erupted as talks over a Palestinian unity government bogged down in disagreement over a cabinet post. A Fatah official denied any responsibility for the killing of Ala al-Haddad, Gaza City commander of Hamas's armed wing, the Izz el-Deen al-Qassam Brigades, and called it the result of a clan feud. Two other people were wounded in the incident, both of them members of a Hamas-led police force. The shootings came shortly before President Mahmoud Abbas met Prime Minister Ismail Haniyeh in Gaza in a bid to resolve a dispute over who would be interior minister, a position that controls security services in a proposed unity government. Under the agreement concluded in Mecca, Hamas will choose who serves as interior minister but Abbas has a veto. Both sides said last week they were on the verge of announcing an agreement but a source close to the talks said on Tuesday the interior ministry dispute had become a "real obstacle" to a final deal. A Qassam spokesman said gunmen from the Fatah-dominated Preventive Security Service had opened fire at their commander's car, killing him. "This is a dangerous and criminal action," spokesman Abu Ubaida said. "We will not stand silent while Palestinian blood is being shed. The Qassam Brigades will punish those killers." A Fatah official denied any security men affiliated to it were responsible. "The Preventive Security Services and its men were not involved at all in the tragic incident in Gaza," the official said. More than 90 Palestinians were killed in factional violence which was largely calmed by a deal reached in Saudi Arabia last month in which Fatah and Hamas agreed to a power-sharing deal. 'REAL OBSTACLE' Abbas has rejected several Hamas candidates for the interior minister's post and Hamas balked at 12 names proposed by Abbas. "Before the end of this week the national unity government will be ready for declaration," Ghazi Hamad, spokesman for the Hamas-led cabinet, said. "The discussions will continue tomorrow." Israel has vowed to boycott the Palestinian unity government, including non-Hamas ministers, unless it recognises the Jewish state, renounces violence and accepts interim peace deals as demanded by the Quartet of Middle East mediators. The unity government agreement contains a vague promise to "respect" previous Israeli-Palestinian pacts. It does not commit the incoming government to abide by those pacts, nor to recognise Israel and renounce violence as demanded by Quartet partners the United States, the European Union, the United Nations and Russia. (Additional reporting by Mohammed Assadi in Ramallah)
