Two U.S. citizens were charged Friday with conspiring to give computer advice, buy watches and do other tasks to help al-Qaida “modernize.”

A vaguely worded indictment unsealed Friday in federal court in Manhattan accused Wesam El-Hanafi of traveling to Yemen to meet with unnamed al-Qaida members in February 2008.

The terrorists “instructed him on operational security measures and directed him to perform tasks for al-Qaida,” the indictment says. While there, he also “took an oath of allegiance to al-Qaida,” it adds.

In February 2008, El-Hanafi bought computer software that allowed him to secretly communicate over the Internet, federal prosecutors allege. That summer, he met with an unnamed co-conspirator and the second defendant, Sabirhan Hasanoff, in Brooklyn to discuss joining al-Qaida, according to the indictment.

The confidential co-conspirator paid $50,000 to Hasanoff, who later traveled to New York City and performed unspecified “tasks for al-Qaida,” the court papers say.

The papers say that the conspiracy included El-Hanafi purchasing seven Casio digital watches, but doesn’t say why.

U.S. Attorney Preet Bharara said in a statement that the men had schemed “to modernize al-Qaida by providing computer systems expertise and other goods and services.” His office declined further comment.

At an initial court appearance Friday afternoon in Alexandria, Va., El-Hanafi, 33, and Hasanoff, 34, waived their rights to a hearing there. They were detained and ordered transferred to New York for a bail hearing.

Prosecutor John Cronan declined to answer questions about the case after the hearing. There was no immediate response to phone messages left with the men’s defense attorneys.