A man accused of being part of an alleged British terror cell attended lectures by radical Muslim cleric Abu Hamza al-Masri, the Old Bailey heard.
Seven men all deny plotting to cause explosions
In a video-taped police interview played in court, Salahuddin Amin, 31, said hearing the speeches in 2001 "made up his mind" to move to Afghanistan.
Mr Amin agreed he attended the lectures at Finsbury Park Mosque during a period of "brainwashing", the jury heard.
He and six other men deny conspiring with a Canadian to cause explosions.
Mr Amin said he had went to the mosque twice before the 11 September attacks in the US, the court heard.
Mr Amin also told detectives in the interview that while in the UK he worked part-time as a taxi driver and put aside as much as £5 or £10 a day to send to "freedom fighters" in Kashmir.
He said he understood the money would be used to buy arms and ammunition, the court heard.
The interview played to the jury took place the day after Mr Amin was arrested on a British Airways flight from Pakistan at Heathrow airport on 8 February last year.
In the interview, he was asked by police whether he had ever attended lectures by "radical preachers".
Salahuddin Amin said he had heard cleric Abu Hamza al-Masri speak
He replied he had attended Finsbury Park Mosque, when it was run by Abu Hamza "shortly before 9/11", the court heard.
He said the preacher had discussed "migrating to Afghanistan".
Mr Amin said on the tape: "He said that wherever in the world there is an Islamic state it is obligatory upon the Muslims to go and support towards that, if there were a fight to make it, to make it stronger."
He was asked by police how Muslims were supposed to give this support, and replied "financially and physically and by fighting".
Later in the interview, he added: "After listening to Abu Hamza speak I've made my mind up that I'm going to move to Afghanistan and stay there."
Mr Amin agreed that he had attended the lectures during a period of "brainwashing" when he had also been watching videos about conflicts in Chechnya and Bosnia, the court heard.
He said in the interview the videos he watched in 2001 showed "a lot of killing" of innocent children, women and old people and they had made him feel "angry".
"They showed Russian planes coming down, bombarding Chechnya," he said.
"In Bosnia, they showed a lot of bloodshed in the streets by Serbs."
In the interview, Mr Amin said the videos "also showed about Israel".
"I found they were like killing people in there, Palestine, and they also said that... the Americans are helping them," he said.
Mr Amin said this was one reason he was "happy" about the 11 September attacks, the court heard.
He also agreed that by the time he went to Pakistan just before the US attacks, he was a radical follower of Islam.
Mr Amin said his main reason for the visit was his sister's wedding, but that he also wanted to "check out" a training camp. However, he said in the interview, he "didn't find anything special" about the training.
"Maybe I didn't see the main training...all I saw was like fitness exercises, that's all, playing football, volleyball," he said.
The defendants were arrested on 30 March 2004, after fertiliser was found stored in a west London depot.
Mr Amin of Luton, Bedfordshire; Anthony Garcia, 23, of Ilford, east London; Nabeel Hussain, 21, of Horley, Surrey; Jawad Akbar, 22; Omar Khyam and his brother Shujah Mahmood, 19; and Waheed Mahmood, 34, of Crawley, are all accused of conspiring to cause explosions likely to endanger life between 1 January 2003 and 31 March 2004.
Mr Khyam, Mr Garcia and Mr Hussain also deny a charge under the Terrorism Act of possessing 600kg (1,300lb) of ammonium nitrate fertiliser for terrorism.
Mr Khyam and Shujah Mahmood further deny possessing aluminium powder for terrorism.