Boris Johnson's Palestine visit has unravelled after organisers cancelled planned meetings amid security fears linked to his pro-Israel stance expressed in recent days
The London mayor said he understood his comments against a trade boycott of Israel have been "very much whipped up" on social media.
He added the office of Palestinian Authority prime minister Rami Hamdallah has advised that security would be "perhaps at risk" if he went ahead with the meetings.
It has been indicated threats of protest were feared.
News of the cancellations came shortly after Mr Johnson arrived in Ramallah in the West Bank. His meeting with Mr Hamdallah will go-ahead.
But two of his three other scheduled events - in which he was due to meet young Palestinians and female business leaders - have been called off.
He will also not attend an affordable housing event, although his delegation is said to be represented.
Mr Johnson told reporters he was pleased to be back in the West Bank but added: "It seems as though there's some anxiety about some meetings - they're worried about some of the safety aspects.
"There's some stuff going on on social media apparently, so rather depressingly we can't do the youth forum and one other meeting."
Reporters were later informed the Palestine Women's Business Forum was also off.
Asked about the security threat, Mr Johnson said: "The reality is we were determined to come here even though it's quite a difficult time at the moment and there's a lot of tension.
"I think that some people have obviously taken remarks I made about the boycott, which is after all British Government policy, they've taken offence of that and that's been very much whipped up on social media.
"So, we had a message from the office of the prime minister that the security with us was going to be perhaps at risk and so we've had to think about those meetings."
Mr Johnson said he hoped they would go ahead but the current situation is that they would not. He went on: "If it's true people are making threats or whatever, that's very sad."
Mr Johnson has spent time in Tel Aviv and Jerusalem during his three-day trade mission, where he has repeatedly criticised calls for a boycott of Israeli goods.
He said a trade boycott would be "completely crazy" and believes it lacks support, with only a "few lefty academics" pursuing the cause.
The Tory MP also questioned the logic of shunning the Middle East's one "functioning democracy".
Ongoing violence in the region has seen several knife attacks against Israelis and a number of Palestinians shot dead by Israeli security forces.
UK MPs have previously condemned the "terror attacks" on Israel's citizens and aggression against Palestinians.
Mr Johnson was due to visit the Sharek Youth Forum, but the group posted a statement saying it has refused to host the mayor as he "fails to acknowledge our very existence as Palestinians".
They said: "Following Johnson's inaccurate, misinformed and disrespectful statement regarding the boycott, divestment and sanctions (BDS) movement on November 9, stating that he 'cannot think of anything more foolish', it is our conclusion, supported by the Palestinian youth that we represent, he consciously denies the reality of the occupation that continues to oppress them and all Palestinians.
"As Palestinians and supporters of BDS, we cannot in good conscience host Johnson, as a person who denounces the international BDS movement and prioritises the feelings of wearers of 'corduroy jackets' over an entire nation under occupation.
"In Johnson's own words, the 'only democracy in the region ... a pluralist, open society" is one that oppresses citizens, confiscates land, demolishes homes, detains children and violates international humanitarian and human rights law on a daily basis.
"We, at Sharek Youth Forum, refuse to give a platform to someone who fails to acknowledge our very existence as Palestinians."