Asked if such e-mail would be identified as coming from the American military, a senior Pentagon official said that "the return address will probably be a dot-com, not a dot- mil," a reference to the military's Internet designation.
To help the new office, the Pentagon has hired the Rendon Group, a Washington-based international consulting firm run by John W. Rendon Jr., a former campaign aide to President Jimmy Carter. The firm, which is being paid about $100,000 a month, has done extensive work for the Central Intelligence Agency, the Kuwaiti royal family and the Iraqi National Congress, the opposition group seeking to oust President Saddam Hussein.
Officials at the Rendon Group say terms of their contract forbid them to talk about their Pentagon work. But the firm is well known for running propaganda campaigns in Arab countries, including one denouncing atrocities by Iraq during its 1990 invasion of Kuwait.
The firm has been hired as the Bush administration appears to have united around the goal of ousting Mr. Hussein. "Saddam Hussein has a charm offensive going on, and we haven't done anything to counteract it," a senior military official said.
Proponents say the new Pentagon office will bring much-needed coordination to the military's efforts to influence views of the United States overseas, particularly as Washington broadens the war on terrorism beyond Afghanistan.
But the new office has also stirred a sharp debate in the Pentagon, where several senior officials have questioned whether its mission is too broad and possibly even illegal.
Those critics say they are disturbed that a single office might be authorized to use not only covert operations like computer network attacks, psychological activities and deception, but also the instruments and staff of the military's globe- spanning public affairs apparatus.
Mingling the more surreptitious activities with the work of traditional public affairs would undermine the Pentagon's credibility with the media, the public and governments around the world, critics argue.
"This breaks down the boundaries almost completely," a senior Pentagon official said.
Moreover, critics say, disinformation planted in foreign media organizations, like Reuters or Agence France-Presse, could end up being published or broadcast by American news organizations.
The Pentagon and the Central Intelligence Agency are barred by law from propaganda activities in the United States. In the mid-1970's, it was disclosed that some C.I.A. programs to plant false information in the foreign press had resulted in articles published by American news organizations.