Hizbollah leader Sheikh Hassan Nasrallah told Hamas's new leader on Saturday to consider the Lebanese guerrilla group under his command following the assassination of Sheikh Ahmed Yassin this week.
In a show of unity between the two Islamist groups, Hamas new chief Khaled Meshaal also addressed thousands of Hizbollah supporters at a memorial service for his predecessor Yassin, whom Israel assassinated this week.
Nasrallah told him: "Consider us in Hizbollah, from the secretary-general and leadership down to our fighters and women, members of Hamas, and soldiers under your command."
The two Islamist groups have long been allies and keep in regular contact. Hizbollah is a staunch supporter of a more than three-year-old Palestinian uprising against Israeli occupation, and the group attacked Israeli posts in a disputed border area on Monday in response to Yassin's killing.
Mourners held pictures of the dead cleric, whose group has killed hundreds of Israelis in suicide bombings, amid a sea of Hizbollah and Palestinian flags.
"I say to our brothers in Palestine: We in Lebanon are with you. Be sure that your blood is our blood and your sheikh is our sheikh. We share the same destiny and this means that our fight is one," Nasrallah said.
Nasrallah told the gathering in Beirut's predominantly Shi'ite southern suburbs that Israelis were planning to plant explosives at unspecified targets, but gave no further details except to say:
"I'm saying that in some of these places we are going to be waiting for them."
Nasrallah, whose group fought Israel's 22-year occupation of southern Lebanon until it withdrew its forces in May 2000, said Israeli suggestions he could be next on its hit list did not scare him.
Meshaal, who lives in exile in Syria, called for similar support from an Arab summit, which was planned for early next week in Tunis but was postponed late on Saturday because of differences between Arab governments on reforms.
Speaking before the summit was postponed, he asked them to support what he called resistance in Palestine and Lebanon and to sever any relations they had with Israeli Prime Minister Ariel Sharon.
Meshaal said Hamas's response to Israel's deadly missile strike against Yassin would be confined to Israel and the Palestinian territories.
"One of our priorities is to respond to Sharon's crime. We will not say what kind of response but I say that our resistance will be confined to fighting the Zionist occupation on Palestinian land," Meshaal said.