BAGHDAD, Iraq – The most feared terrorist group in Iraq, the movement of terror mastermind Abu Musab al-Zarqawi, declared its allegiance to Osama bin Laden yesterday, saying it had agreed with Al Qaeda over strategy and the need for unity against “the enemies of Islam.”

The declaration, which began with a verse from the Koran encouraging Muslim unity, said Mr. al-Zarqawi considered Mr. bin Laden “the best leader for Islam’s armies against all infidels and apostates.”

It said the two had been in communication eight months ago and “viewpoints were exchanged” before the dialogue was interrupted.

“God soon blessed us with a resumption in communication, and the dignified brothers in Al Qaeda understood the strategy of Tawhid and Jihad,” the statement said.

The statement affirmed the “allegiance of Tawhid and Jihad’s leadership and soldiers to the chief of all fighters, Osama bin Laden.” It said the announcement had been timed for the start of the Islamic holy month of Ramadan, when “Muslims need more than ever to stick together in the face of the religion’s enemies.”

“It’s good tidings for our nation … to spite the infidels and frighten the enemies of Islam,” it said.

The statement also endorsed Mr. bin Laden’s goal to “expel the infidels from the Arabian peninsula,” a reference to American influence in the Al Qaeda leader’s native Saudi Arabia, birth place of the Islamic faith.

The Jordanian-born Mr. al-Zarqawi is suspected of about a dozen high-profile attacks in Iraq, including last year’s bombing of the U.N. headquarters in Baghdad and the beheading of numerous foreign hostages.

American and Iraqi officials believe Mr. al-Zarqawi’s movement is centered in the insurgent stronghold of Fallujah, where American troops clashed yesterday with insurgents. However, Tawhid and Jihad banners have been seen recently in Samarra, Ramadi, and even on the streets of the Iraqi capital, Baghdad.

In Cairo, an expert on Islamic militancy, Mohammed Salah, said the claim that Messrs. bin Laden and al-Zarqawi were in regular contact was “more or less a media stunt to frustrate” their common opponent, America.

It appeared the announcement also was aimed at enabling Mr. al-Zarqawi, who has a background as a common criminal, to profit from Mr. bin Laden’s stature among radical Muslims.

Mr. bin Laden, believed to be hiding in Afghanistan or in the border areas of Pakistan, has faded somewhat from public view and recent declarations by Al Qaeda’s leadership have been made by his deputy, Ayman al-Zawahri.

On the other hand, Mr. al-Zarqawi’s group has become highly visible, posting videos on Web sites showing the beheading of foreign hostages and bloody attacks against American troops in Iraq.

“By virtue of his location, al-Zarqawi has more access to the Americans, which will make it easier for Al Qaeda to carry out operations without logistical complications or time delays,” Mr. Salah said. “Bin Laden is on the run and hiding. He’s become a symbol, as opposed to al-Zarqawi’s actual presence on the ground that has made him a definite planner and executor.”

The announcement was made as Mr. al-Zarqawi was indicted in his native Jordan along with 12 other alleged Muslim terrorists on charges of plotting a chemical attack that could have killed thousands of people.

Mr. al-Zarqawi and three of the others will be tried in absentia on charges including conspiring to commit terrorism, possessing and manufacturing explosives, and affiliation with a banned group, according to the 24-page indictment made available yesterday.

The other nine men, who are in custody, face the same charges, except for one man charged only with helping two of the fugitives. If convicted in the military court, 12 of the men face the death penalty.

The indictment alleged that Mr. al-Zarqawi sent more than $118,000 to buy two vehicles that would be driven into Jordan’s General Intelligence Department by suicide bombers armed with explosives and chemicals.

The indictment said the defendants had collected data indicating that the blast would have killed thousands.

Mr. al-Zarqawi’s relationship to Mr. bin Laden and the Al Qaeda leadership had long been the subject of considerable speculation. Although many experts believe Mr. al-Zarqawi had longtime ties to Al Qaeda, others suspected that Mr. al-Zarqawi considered himself a rival to Mr. bin Laden for the mantle of chief defender of the Muslim faith.