Ayman al-Zawahiri's video with picture of Abu Musab al-Zarqawi in background

Al-Qaida's number two leader, Ayman al-Zawahiri, has called for attacks on Israeli and American targets in revenge for Israel's recent offensive in the Gaza Strip.

In an audio recording released Monday on the Internet, Zawahiri urges strikes against the interests of Jews, Americans and all those who he says participate in aggression against Muslims.

He says attacks should not be limited to places in Israel and the Palestinian territories, and he calls on followers to collect money, plan accurately and strike.

Zawahiri also accuses Arab leaders of colluding with the United States and Israel in blockading Palestinians in Gaza.

The authenticity of the recording could not be immediately verified.

The Zawahiri recording was posted on an Islamist Web site that usually releases al-Qaida messages.

In a separate recording released last week, al-Qaida leader Osama bin Laden called on Palestinians to reject negotiations and use "iron and fire" against Israel. A voice described as bin Laden's also urged Muslims to support the insurgency in Iraq as a way to liberate Palestine.

The authenticity of that tape could not be immediately verified.

Some information for this report was provided by AFP, AP and Reuters.