Israeli opposition leader Isaac Herzog expressed his concern about Israel's deteriorating international relations Friday, warning of a growing boycott and a rift with the US administration.

Herzog, head of the Labour party and the Zionist Camp alliance, made the remarks in a lecture at the London School of Economics (LSE), as an invited guest of the university's Institute of Global Affairs.

Under tight security, and with pro-Palestinian protesters outside the building, Herzog dedicated much of his speech to what he described as an "onslaught against Israel all over the world", including the Palestinian-led Boycott, Divestment and Sanctions (BDS) campaign.

Herzog slammed as "totally unacceptable" moves to boycott and isolate Israel, urging the international community to "encourage negotiations, not punishments." Declaring himself ready to "defend Israel's good name" and be its "representative wherever it is needed", Herzog declared: "I am here to combat it [BDS] – I am here exactly for that purpose."