By Ayesha Ahmad, IOL Washington correspondent 

WASHINGTON, March 20 (IslamOnline & News Agencies) - The U.S. State Department authorized the voluntary departure of diplomats and their families from Pakistan late Monday, March 20, warning Americans to defer travel to Pakistan as U.S. authorities worked with Pakistan on the investigation into Sunday's church attack that killed two Americans. 

"We are making every effort to work with Pakistan on the issue," State Department spokesman Richard Boucher said Tuesday, but there have as yet been "no claims of responsibility for the attack… no arrests," he added. 

He did not comment on what he said was "a lot of speculation about motives," adding only that the investigation was continuing and that the U.S. was working "very, very closely" with Pakistani authorities. 

"We've dispatched a team of special agents from the Bureau of Diplomatic Security… to assist in the investigation," he said. 

Aside from the Americans - the wife and teenage daughter of U.S. diplomat Milton Green - three others were killed in the attack, including a Pakistani woman and an Afghan man, Agence France-Presse (AFP) reported. 

The fifth badly mutilated victim, still unidentified more than 48 hours after the attack, is believed to be the attacker as no other worshippers have been reported missing, AFP said. The Pakistani government may send samples to the United States for DNA tests to identify the man, an interior ministry spokesman told AFP.

Forty-six mainly foreign worshippers, including fourteen non-government Americans, were wounded in the attack. 

Meanwhile, Boucher said that "preparations are ongoing for the repatriation of our employees," but the U.S. is not considering a complete pullout of diplomatic personnel. "We're not pulling everybody out," he said. "They have an important mission to do" and will be assisted in completing it safely, he added. 

In a statement released Monday, March 18, the State Department said that "eligible family members of Embassy and Consulate personnel in Pakistan" were authorized to leave Pakistan on a voluntary basis. 

"The consulates in Peshawar, Lahore and Karachi will remain open for American citizen services but not visa services," said the warning. 

"The U.S. embassy in Islamabad is open for all services, including visa services. However, from time to time, the missions in Pakistan may temporarily close or suspend public services as necessary to review their security posture." 

A CNN report Tuesday, March 19, said that an "authorized departure" signifies a security situation considered dangerous enough to allow family of U.S. personnel to leave their posts at the expense of the federal government. 

Boucher said Tuesday that the decision on this warning was made based on the best information available at the time, and was focused on keeping diplomats with their families. He said that Washington was offering full assistance and support to any Americans affected by the attack. 

The last authorized departure for U.S. officials in Pakistan, declared one week after the September 11 attacks, ended on January 29, the CNN report said; dependents of U.S. diplomats who had been gone for months were allowed back as recently as March 2 (including Green's wife Barbara and their daughter Kristin), Boucher told reporters on Monday. 

"Clearly we all want to be as careful as possible with our personnel, but, as you know, the departure of our dependents and non-emergency personnel had gone on for months," he said. "People at posts were looking forward to having their families back with them, and at that time we operated on the best security information we had." 

Monday's statement also warned U.S. citizens to defer traveling to Pakistan, citing the possibility of civilian structures being targeted as well as official areas.  

"Americans who reside or visit Pakistan should exercise maximum caution and take prudent measures," said the statement. "They should avoid crowds, demonstrations and areas where Americans generally congregate."