Updated

Israeli officials said Sunday that a Hamas commander assassinated in Dubai played a central role in smuggling weapons from Iran to Gaza militants. But they refused to say whether Israel was responsible for killing the man it had sought for two decades.

Leaders of the Iranian-backed Hamas have accused Israel of killing Mahmoud al-Mabhouh in a posh Dubai hotel on Jan. 20, though they have provided little evidence to support the claim. Dubai authorities have said a "professional criminal gang" with European passports was likely behind the killing.

The defense officials said al-Mabhouh was key to moving arms made in Iran or funded by the Iranian government to Gaza, which is ruled by Hamas. They spoke on condition of anonymity because they were discussing confidential information.

Al-Mabhouh was wanted by Israel for his role in the 1989 kidnapping and killing of two Israeli soldiers on leave. But Israel has neither confirmed nor denied involvement in the killing.

There have been conflicting details about how Al-Mabhouh was killed.

Talal Nassar, an official in Hamas' media office in Damascus, said over the weekend that al-Mabhouh had been "poisoned and electrocuted in his hotel room in Dubai." But Al-Mabhouh's brother, Hussein, 49, who lives in the Jebaliya refugee camp in Gaza, said his brother "died by electric shock and suffocation with a piece of cloth."

Al-Mabhouh's brother accused Israel.

"Who had an interest in rubbing him out? Israel," Fayek al-Mabhouh told Israel's Army Radio from Gaza on Sunday. "He wasn't connected to any gang. He wasn't a criminal."

Abu Obeida, Hamas' military spokesman in Gaza, said Mahmoud al-Mabhouh was passing through Dubai en route to another country when he was killed, but did not say which country.

Iran has acknowledged bankrolling Hamas but has never admitted to arming the militant group, which wrested control of Gaza from the rival Fatah faction in June 2007. Israel is convinced Tehran has become a main pipeline for arms to Gaza ever since the Hamas takeover.

Stopping the flow of weapons to Hamas rocket squads has been a top priority for Israel. The air force pounded smuggling tunnels under the Gaza-Egypt border during its three-week war in Gaza last year and continues to target them sporadically. The tunnels have been built to skirt an Israeli and Egyptian blockade of the tiny Palestinian territory.

Fayek al-Mabhouh claimed his brother had survived two Israeli assassination attempts, including an attempt six months ago to poison him in Beirut.

Hamas posted pictures of al-Mabhouh's body on its Web site Sunday. The photos showed the body wrapped in a white burial shroud and a green Hamas flag and headband. Al-Mabhouh appeared to have been beaten, with bruises and welts on his nose and cheeks.

Israel has been linked to previous attacks on Hamas figures outside the Palestinian territories and other efforts to halt suspected arms shipments to Gaza. In most cases it has refused to comment on the allegations against it.

Last month, two Hamas men were killed in a mysterious blast in Beirut. Hamas said Israel was a suspect but did not openly accuse it of the killings.

The leader of Hamas' Damascus-based leadership, Khaled Mashaal, survived an Israeli poisoning attempt in Amman, Jordan, in 1997.

Last year, Sudan — a close ally of Iran and Hamas — accused Israel of attacking a convoy in a remote mountainous desert region of northeastern Sudan. Media reports said the attacks targeted convoys smuggling weapons en route to Hamas-ruled Gaza.

Israel is also suspected of assassinating a senior military commander from the Iranian-backed Lebanese guerrilla group Hezbollah in Damascus in 2008, and was accused by Iran earlier this month of slaying an Iranian nuclear physicist.

Israeli Cabinet Minister Uzi Landau dismissed Hamas allegations that he brought the assassins with him when he traveled to Dubai earlier this month to attend an international conference on renewable energy.

"What we are seeing here is the wild Middle Eastern imagination coupled with Palestinian anger that the Israeli flag is formally flying at a conference at a hall in Abu Dhabi," Landau told Israel Radio.