Federal prosecutors on Tuesday sought to attack the credibility of a Pakistani immigrant accused in a subway bombing plot, suggesting he was an angry young man who was prone to violence.

Shahawar Matin Siraj, 23, testified Monday that he never had a violent thought before he met a paid police informant who inflamed his anger toward the United States.

On Tuesday, Prosecutor Marshall Miller cited conversations that took place before Siraj met the informant in which he ranted about wanting to beat up or stab rivals.

"I said many things that were hurtful," said Siraj, who claimed the threats weren't real.

The prosecutor had earlier alleged that Siraj told a friend in 2002 that he approved of suicide bombings. Siraj said he did not remember the conversation.

Siraj is accused of planning to bomb the Herald Square subway station, near Macy's flagship department store, during the 2004 Republican National Convention. If convicted, he faces up to 20 years in prison.

Defense attorneys have characterized Siraj as a naive young man who was entrapped by the older informant, who was paid to infiltrate a Brooklyn mosque.

Testifying Monday, Siraj said he came up with the subway plot to impress the informant, Osama Eldawoody. Siraj said he had become jealous when Eldawoody praised another bombing plan put forward by accused coconspirator James Elshafay, who has pleaded guilty.

On the stand, Siraj claimed that he tried to back out of the plan when Eldawoody could not guarantee that civilians would not be hurt.