Palestine Solidarity Campaign head Hugh Lanning denied entry over his connection to the boycott movement.
The BDS movement, launched in 2005 as a non-violent campaign to press Israel to obey international law and end its illegal occupation of Palestinian territory, has gathered momentum in recent years.
BDS supporters object to Israel’s continued building of illegal settlements on Palestinian land.
They also accuse Israeli forces of killing and mistreating Palestinians under the pretext of maintaining security. They say neither US universities nor businesses should have any links to their Israeli counterparts.
US Ambassador to the UN Nikki Haley told attendees that the BDS mission was misguided.
“How tragic is it, that of all countries in the world to condemn for human rights violations, these voices choose to single out Israel? We should boycott North Korea. We should sanction Iran. We should divest from Syria, not Israel,” she said.
Riyad Mansour, the Palestinian ambassador to the UN, watched the summit and told Al Jazeera the anti-BDS campaign would not succeed.
“Why do you bring your supporters and followers to the UN to abuse the facilities and to threaten injecting this issue on the agenda of the UN … If you want to go and combat BDS, go to campuses and universities and conduct your business there,” Mansour said.
Hundreds of university students were invited to the summit at the UN to learn how to counter BDS’s campaign.
“The anti-BDS summit was a call to arms in a very visible location,” Al Jazeera’s Rosiland Jordan, reporting from UN headquarters in New York, said. “But there is no way to predict whether it will ultimately succeed.”
Israel also announced on Wednesday it was cutting its already reduced required annual payment to the UN by $2m to protest against resolutions taken against it in various UN forums.
The General Assembly requires all 193 UN member states to pay a percentage of its regular budget, based on their GDP. According to the UN Secretariat, Israel is expected to pay about $11m this year, or 0.43 percent of the regular budget.
Israel’s refusal to pay $2m of its dues will put the country in arrears, but it won’t immediately lose its vote.
Under Article 19 of the UN Charter, any country in arrears of its dues payments in an amount that equals or exceeds the contributions due for two preceding years can lose its vote in the General Assembly.
Nahshon said the money it was holding back would be used for development projects in countries that support Israel in international organisations.
A UN report this month accused Israel of practising apartheid in the occupied West Bank. That report was withdrawn and Rima Khalaf, the senior UN official with responsibility for it, resigned in protest.
“A few weeks ago … together with our American friends, we made clear that Rima Khalaf, an anti-Semite, a promoter of BDS, will not be tolerated in the halls of the UN,” Israel’s ambassador to the UN, Danny Danon, told attendees at the BDS summit.
Khalaf has dismissed previous Israeli allegations of anti-Semitism and has stood by the report.
Separately, David Friedman was sworn in as the US Ambassador to Israel on Wednesday.
Friedman has no diplomatic experience but is a longtime friend of US President Donald Trump and worked for him as an lawyer. Friedman is a supporter of the expansion of Israeli settlements on land belonging to Palestinians.
He also favours moving the US embassy from Tel Aviv to Jerusalem. The relocation is opposed by many US allies because both Israel and the Palestinians claim the city as their capital.