A young American who pledged allegiance to the Islamic State group was arrested in New York on Wednesday after trying to stab an FBI agent, officials said.

Fareed Mumuni, 21, is the third suspect detained in connection with an alleged plot to bomb the city on behalf of IS, which has declared a "caliphate" based in Iraq and Syria.

Munther Omar Saleh, a 20-year-old student at an aeronautics college in Queens, has been identified as one of the other suspects.

Mumuni was arrested at his home on Staten Island after lunging at an FBI special agent with a kitchen knife. The agent was wearing body armor and sustained only minor injuries.

A search of his mother's car, which he also used, unearthed a duffel bag containing another large kitchen knife, court papers said.

Mumuni allegedly confessed to pledging allegiance to IS, intending to travel to IS-controlled territory and to discussing how to build a pressure cooker bomb with Saleh.

He was expected to appear before a federal court in Brooklyn later Wednesday. Prosecutors will demand custody without bail. He faces a maximum sentence of 20 years if convicted.

Saleh, who allegedly translated IS propaganda into English, was arrested last Saturday -- also after allegedly trying to attack a surveillance officer with a knife.

Mumuni and Saleh discussed ways to attack law enforcement -- using guns and a bomb, prosecutors say.

- Visited 'spy' store -

Court papers say that Saleh also confessed to pledging allegiance to the IS group and prosecutors say his browsing history provided an alarming record of his twisted ideology.

In September 2014 he allegedly tweeted "i fear AQ (Al-Qaeda) could be getting too moderate" and this year expressed support for the gunmen who attacked the Charlie Hebdo magazine in France.

In other tweets he also praised the burning to death of a captured Jordanian pilot and the beheading of a Japanese journalist by IS.

On May 7, he allegedly told an informant he was "trying to do an op" -- shorthand for operation -- and emailed himself information from the Internet on how to build a pressure cooker bomb.

Prosecutors allege that Saleh and the third suspect searched online for components and tools to make a bomb, such as a pressure cooker, drill, LED light, propane and a garden hose.

At the end of May, Saleh looked up New York landmarks and tourist attractions on the Internet to assess potential targets for a bomb attack, the court papers said.

Earlier in the month he allegedly visited a "spy" store in Queens, which sells microphone detectors and hidden cameras, although he appeared to leave without purchasing anything.

He subsequently bought a digital wrist watch from another store, which the criminal complaint signed by an FBI agent, pointed out "may be used as a timer for an explosive device."

And he searched online for fire arms, knives, ammunition, masks and a bulletproof vest as well as beards and wigs, which could be fashioned into disguises.