JERUSALEM — The Palestinian Arab premier cut short a foreign tour yesterday to address the security crisis in Gaza after a senior Hamas commander who also worked as a judge was shot dead.

But Prime Minister Haniyeh, who heads the Hamas-controlled government, sought to play down the gravity of the worsening situation when he denied that civil war was about to erupt.

Speaking in Khartoum, Sudan, Mr. Haniyeh said: “We want to assure you that words such as civil war don’t exist in our dictionary.”

But the fact that he was heading home two weeks early added to the sense of crisis following the murder on Monday of a senior Fatah commander’s three children and subsequent skirmishes between the rival factions.

The bloodletting continued when Bassam al Fara, 30, an officer in the military wing of Hamas, was shot dead by gunmen in Khan Younis.

Fara, who also worked as a judge in an Islamic court, was killed outside the courthouse where he worked. A witness said he was dragged out of a taxi by armed men and shot.

With Hamas immediately blaming Fatah — the faction headed by the moderate Palestinian Arab president, Mahmoud Abbas — and Fatah accusing Hamas of provocation, more tit-for-tat killings are believed to be likely.

Mr. Haniyeh was on a month-long tour intended mainly to generate funding for his beleaguered government.

After winning January’s general election, the Hamas government has been crippled by a financial boycott led by Israel and its allies in protest of Hamas’s hard-line policies toward the Jewish state.

This has forced the government to look for backing from the Islamic world. Mr. Haniyeh spent several days in Iran, which has suddenly emerged as the Palestinian Arabs’ largest financial backer, committing about $250 million this year alone.

His willingness to cut short this financially important trip reflected the gravity of the crisis in the territories and Gaza in particular.

“We need the prime minister to be here now to resolve the internal problems,” one of his political advisers, Ahmed Youssef, said.

According to the Palestinian Center for Human Rights, 248 Palestinian Arabs have died in civil disorder this year alone, including 34 children.

In further violence last night, a man threw a grenade at a Hamas rally in a refugee camp the Gaza Strip, causing several casualties. The rally in Nusseirat was being held to protest the recent violence.