Islamabad, Pakistan ? Pakistan’s president vowed on Friday to hunt down every one of Wall Street Journal reporter Daniel Pearl’s kidnappers and to treat terrorism with “an iron hand.” Police said they were no longer restrained in the hunt for the kidnappers by concern for the safety of the hostage.

Condolences and expressions of outrage poured out from Pakistan’s president, Cabinet ministers, journalists and even some Islamic militant groups after a grisly videotape revealed Pearl’s brutal slaying at the hands of extremists nearly a month after his abduction in the southern port city of Karachi.

“This incident has enhanced our resolve and in the days to come, I will deal with all kinds of terrorism with an iron hand,” Pakistani President Pervez Musharraf vowed.

In a statement Friday, Pearl’s widow, Mariane, who is seven months pregnant, said her husband’s killers could not defeat his spirit and that she would tell their still unborn son that his father had worked to end terrorism.

Thanking “all of the people throughout the world who have given Danny and me support and encouragement,” she said the struggle against terrorism was everyone’s responsibility.

Deputy Secretary of State Richard Armitage spoke with her Friday morning, department spokesman Richard Boucher said.

Armitage expressed the State Department’s condolences and assured her of “the commitment to bring to justice the people who are responsible for this horrible action,” Boucher said.

Four people have been arrested and charged in the case, including a British-born Islamic militant who admitted in court this week that he was behind the kidnapping. A huge manhunt is under way for four other suspects, Interior Minister Moinuddin Haider told reporters.

Once they are apprehended, Haider said, “the whole net will be broken. We know their names and we know their identity.”

Yet Pearl’s body has not been found, nor was there information on where or when he was killed. The remaining suspects have been able to elude the government’s massive dragnet, which had included detention of their family members in an effort to flush them out.

Police searched Friday in a district of Punjab province for Amjad Faruqi, who is believed to have carried out the kidnapping.

Faruqi is believed to have used the alias Imtiaz Siddiqi when he telephoned Pearl twice on the day he was abducted, police said.