DAMASCUS, (Reuters) – Israel assassinated a senior Hamas military commander in Dubai who played a major role in a Palestinian uprising in the 1980s, an official in the Islamist group said on Friday.

Israeli officials had no immediate comment.

Mahmoud al-Mabhouh, an Israeli target since engineering the capture of Israeli soldiers two decades ago, was killed on Jan. 20, Izzat al-Rishq told Reuters in the Syrian capital Damascus.

Mabhouh’s death lengthens Hamas’s list of what it describes as “martyrs”, and constitutes another setback for the group, which refuses to abandon its fight against the Jewish state.

Israel has killed dozens of leaders and military figures in Hamas, which was founded two decades ago as a religious resistance movement against Israeli occupation.

“I cannot reveal the circumstances (of the killing). We are working with the authorities in the United Arab Emirates,” said Rishq, who is a member of Hamas’s politburo.

Dubai officials had no immediate comment.

Rishq said Mabhouh, 50, was an “important” member of Izz el-Deen al-Qassam brigades, Hamas’s military wing named after a Syrian religious leader who fought British colonial forces in Palestine in the 1930s. He said the brigades “will respond (against Israel) in the appropriate time and place”, but Hamas will not let the killing derail efforts to arrange for a prisoners’ exchange deal between Hamas and Israel that have run into difficulties.

“We still want these efforts to continue. This deal is to the interest of the Palestinian people,” Rishq said.

Mabhouh, who was born in the Gaza Strip but had been living in Syria since 1989, was assassinated a day after he arrived in Dubai, he added. His funeral is due to take place later on Friday at the Palestinian refugee camp of Yarmouk on the edge of Damascus.

Another Palestinian source said Mabhouh was found dead in his hotel room in Dubai without any injuries to his body. He had barricaded the door of his room with chairs, a standard precaution by a man who felt that Israeli intelligence has been after him for 20 years.

“It seems that an autopsy was ordered and found traces of poison in his body. Mabhouh was also ill. Hamas controls the information on this,” the source said. “Being in Syria, Mabhouh was not directly involved in Hamas’s military operations. He was one of their main military guys, although not a crucial figure.”

Syria and Iran are the main backers of Hamas, which controls the Gaza Strip.

Rishq, who lives in exile in Damascus, along with several of Hamas’s main figures, said Mabhouh engineered the capture of two Israeli soldiers during the Palestinian uprising in the 1980s. The soldiers were later killed.

Mabhouh was imprisoned several times by Israeli forces. Israel razed his home in Gaza, Rishq added.

A diplomat in Damascus said it was too early to say if Mabhouh’s past was linked to his death.

“The Israelis have a long memory for sure, but one cannot draw conclusions yet. It might be easier for the Israelis to kill him in Dubai than in Damascus,” the diplomat said.

The United States, which has started a rapprochement with Damascus, wants Syrian authorities to help neutralise Hamas as an armed Middle East force.

Syria, which is seeking peace with Israel, resisted U.S. pressure several years ago to expel the Hamas leadership.

Hamas also has a presence in Lebanon. A bomb in Beirut killed two of its members in December.