Kapito was talking about bonds at the Bank of America Securities Financial Services Conference in New York when someone at the event shouted questions about BlackRock's responsibility to exit investments in fossil fuels.
The panel moderator, Craig Siegenthaler, managing director at BofA Global Research, asked to call security and Kapito said he would respond "at the appropriate time, not interrupting the event".
The live webcast from BlackRock's website switched to playing music. This happened twice more over the next few minutes.
Climate change activists have targeted BlackRock for years, asking the world's largest asset manager to stop investing in fossil fuel companies.
BlackRock has rejected the idea of divesting from fossil fuels, saying instead it wants to engage with companies on the transition to a low-carbon economy.
The firm has faced criticism from many sides in the debate, with environmentalists protesting it does too little to press for change at fossil fuel portfolio companies, and Republican U.S. politicians accusing it of boycotting energy stocks.
(Reporting by Davide Barbuscia; Editing by Chizu Nomiyama)
