"We are committed to intensifying armed attacks against coalition forces and their spies and agents... in response to the Sharm al-Shaikh conference - a sordid and suspect farce," said Wednesday's statement signed by groups including the al-Qaida Group in the Land of Two Rivers (Iraq).
The international conference that wound up in Egypt on Tuesday brought together the world's major powers, neighbours of Iraq, the United Nations and others to support the process of political transition in Iraq, including the 30 January elections.
Al-Zarqawi's group said it backs the call of Saddam Hussein's Baath party, which issued a previous statement calling for action against US-led forces in Iraq.
The signatories said they signed "the statement written by the Iraqi Baath party, not because we support the party or Saddam, but because it expresses the demands of resistance groups in Iraq".
The authenticity of the statement could not be immediately verified.
Saddam's Baath party, in power from 1968, was outlawed following the US-led invasion of March 2003 that toppled his government.
Muslim scholars criticised
However, the party continues to exist underground, and charged on Monday that the Sharm al-Shaikh conference was a "sham".
It also accused Egyptian President Husni Mubarak of wanting to use "plotters and mediators" at the forum for US benefit.
"Numerous Arab regimes neighbouring Iraq, following the lead of Mubarak's regime... took part, along with the puppet power [Iraqi interim government], in the massacre of Iraqis, the destruction of their property, as well as the training and arming of [Iraqi] policemen and national guardsmen," the statement said.
"The Sharm al-Shaikh conference took place at the US's request... the American occupier wants to bring together Arab forces which plot against the Arab people and against the future, against the national unity and Arab essence of Iraq - a dear aim of Zionism."
"Numerous Arab regimes neighbouring Iraq, following the lead of Mubarak's regime... took part, along with the puppet power [Iraqi interim government], in the massacre of Iraqis, the destruction of their property, as well as the training and arming of [Iraqi] policemen and national guardsmen"
Internet statement attributed to Abu Musab al-Zarqawi
According to a separate recording on another website, al-Zarqawi also hit out on Wednesday at Muslim scholars for "betraying the mujahidin", especially in Iraq and Afghanistan.
"Oh scholars of the nation... you have betrayed us in the darkest circumstances. You have delivered us to our enemy... you have left the mujahidin to confront [alone] the greatest world power," said the voice attributed to al-Zarqawi, who has a $25 million US bounty on his head.
"Until when will you abandon the nation to the tyrants of the east and of the west, who are inflicting the worst suffering, cutting the throats of the mujahidin, the best children of the nation, and taking its riches?" said the recording.
Zarqawi relative arrested
"Hundreds of thousands of Muslims are having their throats cut by the infidels, because of your silence. If you are not knights of God's war, let women do it."
The tape was not posted by al-Zarqawi's designated media coordinator, Abu Maysara al-Iraqi, and it's authenticity could not be verified.
The message came as Iraqi security forces were searching for al-Zarqawi north of Baghdad after receiving reports of his presence in the region.
He is accused by the US military of some of the deadliest attacks in the war-wracked country and the execution of hostages.
"Oh ulamas of the nation... you have betrayed us in the darkest circumstances. You have delivered us to our enemy... you have left the mujahidin to confront [alone] the greatest world power"
Recording attributed to Abu Musab al-Zarqawi
The tape surfaced as Jordanian security forces detained the husband of al-Zarqawi's sister in Amman.
Relatives of Salih Ilhami told Aljazeera that the authorities arrested him after storming his home on Tuesday night. The authorities also detained al-Zarqawi's nephew.
Sources from Ilhamy's family added that al-Zarqawi's first wife and his sons left their home in al-Zarqa, near Amman, and dissappeared about three months ago.