The Israeli army said Monday it has warned its top officers to be on guard when traveling abroad following the mysterious death of a Hamas commander in Dubai.

Hamas has accused Israel of carrying out the Jan. 20 slaying of Mahmoud al-Mabhouh and vowed revenge, hinting it could attack Israeli targets abroad. Hamas has historically limited its attacks to Israel and the Palestinian territories.

Although Israel has not acknowledged any role in the killing, military officials said Monday they were taking the threats seriously and had instructed senior officers, military attaches and soldiers on study leaves to exercise caution when traveling abroad.

The officials said the military fears Hamas could try to capture Israeli officers outside the country. They spoke on condition of anonymity because they were discussing a sensitive security matter.

Hamas has said al-Mabhouh was electrocuted and poisoned in his Dubai hotel room. It was one of several mysterious deaths of Arab militants attributed to Israel's Mossad spy agency over the years.

Israeli security officials have claimed al-Mabhouh played a critical role in smuggling more advanced rockets from Iran to Palestinian militants in the Hamas-ruled Gaza Strip.

Hamas already possesses a formidable arsenal of shorter-range weaponry, and Israeli officials consider these longer range rockets that could strike major population centers in central Israel to be an unacceptable threat.

Hamas has been quiet about the reason for al-Mabhouh's travels, though a brother says he was on a mission for the militant group. One senior Hamas figure, Osama Hamdan, denied al-Mabhouh was on a special assignment or that he was planning to head to Iran.

Iran has long been suspected of supplying weapons to Hamas, which smuggles supplies in through hundreds of tunnels snaking under Gaza's sealed border with Egypt.

Israel carried out a broad military offensive against Hamas militants last year. The operation, meant to halt Hamas rocket fire, killed some 1,400 people, including an estimated 900 civilians, according to Palestinian and international human rights groups.

On Monday, an Israeli court indicted two suspected Hamas members on charges they plotted attacks against civilian targets across Israel.

Marad Kamel, 24, and Marad Namr, 25, allegedly were recruited by Hamas while living in Jordan, Israel's Shin Bet internal intelligence agency said. The targets included central bus stations in Beer Sheva and Jerusalem, a Jerusalem mall, Tel Aviv's hotel district and a military base in the Tel Aviv area, the agency said.

The men were arrested on Jan. 3 but there was a gag order on their detention. The two live in Jerusalem and have Israeli identification cards that allowed them to travel freely throughout Israel.

The Shin Bet said it recovered a portable flash drive that contained photos, video and other plans for the attacks.

The men were charged with contacts with a foreign agent, membership in a terror organization, aiding and abetting the enemy during wartime and espionage.