Mohammed Emwazi, the man otherwise known as "Jihadi John", wanted to carry out "acts of terrorism" in Tanzania, one of its top officials believes.
Emwazi was refused entry to Tanzania in 2009 for being drunk and abusive, custody records from the time show.
He has claimed he was on holiday with two friends when they were stopped and interrogated under orders from MI5.
Tanzania's home affairs minister Mathias Chikawe said there was no tip-off, but Emwazi "wanted to harm us".
Emwazi, who is in his mid-20s and from west London, has been identified as the masked jihadist in several Islamic State videos in which hostages have been beheaded.
He has said he was a student looking forward to a safari holiday when he flew to Tanzania's Dar es Salaam airport, from The Netherlands, six years ago.
He said that when he arrived, he was stopped, arrested and accused of wanting to joining the al-Qaeda-linked Somali terror network al-Shabaab.
But speaking to the BBC's East Africa correspondent Ed Thomas, Mr Chikawe said there was no contact from any intelligence agency relating to Emwazi, and the men were only stopped because of their behaviour.
"We had no information whatsoever from any organisation or anybody for that matter," he said.
"They were in a state of inebriation - highly drunk. And they were cursing and saying all the bad words you can think of.
"So the immigration officers detained them and asked them questions, saying, 'Why do you behave like this? Who are you? Why are you coming here?'."
Looking for CCTV
In emails written to campaigners at advocacy group Cage, Emwazi said he had been threatened at gunpoint and was later told to ask the British government why he had been stopped.
But Mr Chikawe said his claims were untrue.
"He was actually detained by a lady, a young lady. She could not interrogate, she could not threaten the three of them," he said.
"It's not true, we just asked them questions.
"If he is saying anything other than what I'm telling you, then he is (lying)," he added.
He said there was a "very close" relationship between Britain and Tanzania because of historical ties. He has asked the Tanzanian authorities to investigate Emwazi's time in Tanzania.
"I've asked them to look for the CCTV footage if there is any, just to see exactly what happened," he said.
"Because for us at that time he was just like any other visitor trying to enter Tanzania, he wasn't special."
He said he believed their intent had been to cause harm.
"They must have wanted to do some terrorist acts. I think maybe they wanted to harm us, definitely," he said.
"We have been hit terrorists. The American embassy was blown up. We feel we are targets, and we don't want to be victims. We shall always defend ourselves."
A custody record dated 23 May 2009, and written in Kiswahili, requests that Emwazi and two friends "be detained after they refused to return back to Amsterdam using KLM 569 after being refused entry to the country".
The document names Emwazi, Ally Adorus and Marcel Schrodel.
Adorus, a British citizen, is now a convicted terrorist serving a prison sentence in Ethiopia.
Schrodel is said to have been known to German security services.
Mohammed Emwazi timeline:
- 1988: Born in Kuwait, moves to UK in 1994
- 2009: Completes computing degree at University of Westminster
- Aug 2009: Travels to Tanzania with two friends for safari but refused entry at Dar es Salaam. Put on flight to Amsterdam. After questioning there, returns to Dover
- Sept 2009: Travels to Kuwait to stay with father's family
- July 2010: Returns to UK for short stay but told he cannot return to Kuwait as visa denied
- 2012: Passes Celta English language teaching course
- 2013: Changes name by deed poll. Tries to travel to Kuwait but is stopped. Disappears. Parents report him missing. Police tell family four months later he has entered Syria
Source: Cage, London-based campaign group