Washington (CNN) -- Five men missing from the Washington area are in Pakistani police custody, the FBI said Thursday, a day after Pakistani authorities arrested several men whom they described as Americans and accused them of plotting terrorist attacks.
In a statement, the FBI said Pakistani authorities detained the men -- four of whom it said were found to have American passports -- on Wednesday, "after they came to the attention of police." The statement did not give further details and did not identify the men.
"Although positive identification is still pending, the FBI believes they are the missing individuals," the bureau said.
An FBI special agent and two other U.S. government officials from the U.S. Embassy have spoken with some of the men, the FBI said.
Pakistani police said they are confident the men were planning terrorist acts, according to Tahir Gujjar, deputy superintendent of police in Sargodha, where the men were arrested.
Gujjar told CNN that a preliminary investigation suggests that the men came to Pakistan to wage jihad and had sought to link up with the Jaish-e-Mohammed and Jamaat ud Dawa militant organizations, neither of which showed interest, he said. The men wanted to martyr themselves, he said.
Pakistani officials arrested five of the men Wednesday, and a sixth man -- the father of one of the five -- was arrested afterward, Gujjar said.
Usman Anwar, head of the district police of Sargodha, said the men initially made contact with Pakistani militants through YouTube in August while they were still in the United States.
The men were watching videos of Americans being killed in Afghanistan and had posted comments, which caught the attention of the militants, Anwar said.
After contact was made, a Yahoo e-mail account was set up so the men and militants could communicate, Anwar said.
"They were using a typical method that has been used by very notorious organizations," he said, explaining that e-mails were never sent from the account; rather, each side left messages as drafts, which were deleted after they were read.
After the arrests, authorities discovered that the men had received their final orders, including their "exact task, going to a particular spot ... and the exact method of how to get there," Anwar said.
He did not disclose further details.
State Department spokesman P.J. Crowley said that a team made up of U.S. Embassy security officials and FBI officials met with the men Thursday, and that consular officials will probably meet them Friday.
"It's important to emphasize at this point, we are in an information-gathering phase, but we have met with them," he said in a briefing Thursday with reporters.
"We're going to find out how they made their way from Washington, D.C., to Pakistan, why they were there, what their intentions were," he said. "At this point, we've reached no judgments."
A U.S. law enforcement official who was not authorized to speak on the record said FBI agents based in Pakistan were interviewing the men, and added that some based in the United States would probably travel there as well. The official said he had seen reports of a sixth man arrested, but did not comment.
The official, who would not provide a list of those arrested, said authorities are looking at computers the men were using in the United States, as well as cell phones and anything else they may have carried with them.
Pakistani officials said Thursday that the six men are three Pakistani-Americans, an Ethiopian-American, an Egyptian-American and an Eritrean-American.
President Obama said that he envisioned "a series of investigations" into the arrests, but he said he preferred not to comment on them.
The arrests followed a Wednesday raid on a home in Sargodha, about 120 miles south of Islamabad, Pakistani police said.
In the raid, investigators found laptops and maps of Pakistan containing highlighted areas that correspond to regions where terrorists have been active, police said.
A Pakistani official told CNN the men arrived in Karachi on November 30 and went on to Lahore and then Sargodha, the official said. The arrests came at the behest of local police, the official said.
Subira Farouk, the wife of Khalid Farouk and the mother of Umar Farouk -- both arrested -- said she and her husband had traveled to Pakistan to arrange a marriage for Umar, and to her surprise, her son had arrived in the country shortly afterward.
Farouk, who spoke to CNN in Sargodha on Thursday, described her son as a business student at George Mason University who she said would never plan a terrorist attack.
The mother said that she had spoken to her son before he had arrived in Pakistan and that he had mentioned going to a conference with friends.
Afterward, she said she did not hear from him, prompting her to grow concerned. After speaking with his friends' parents, she said she believed that they had been kidnapped.
The families contacted the Council on American-Islamic Relations and U.S. law enforcement authorities, who advised her to stay in Pakistan, she said.
Later, Farouk said she received a call from a relative in Pakistan who said her son was in the country with several friends. She said she was relieved, thinking her son had surprised her, but authorities then arrested her husband, her son and his friends.
The Council on American-Islamic Relations said Wednesday that it was assisting in the investigation of "five Muslim young men from Virginia who left the country recently under mysterious circumstances."
CAIR spokesman Ibrahim Hooper told CNN that one of the missing youths was a student at Howard University and that all five knew each other.
Nihad Awad, CAIR executive director, told reporters that one left a video behind. "I was disturbed by the content of it," he said.
One person appeared in it and made references to "the ongoing conflict in the world, and that young Muslims have to do something," Awad said. He said the video "juxtaposed certain verses of the Quran," and he suggested there was a misunderstanding of those verses and their potential misuse.
The video is about 11 minutes long, he said, and is "like a farewell."
CNN's Arwa Damon, Carol Cratty, Jeanne Meserve and Samson Desta contributed to this report.