WASHINGTON — Google chief executive Sundar Pichai paid a rare visit to Washington on Friday to defend the search giant against allegations that it silences conservatives online, part of an effort to defuse political tensions between the company and Congress ahead of a hearing later this year.

At a gathering with a dozen Republicans, House GOP Leader Kevin McCarthy of California stressed to Pichai that party lawmakers are concerned about ‘‘what’s going on with transparency and the power of social media today,’’ particularly given the fact that Google processes 90 percent of the world’s searches.

Google long has denied that it censors conservatives. Pichai explained during the roughly hour-long private meeting how the company sets up its teams and codes its algorithms to prevent bias, according to a person who attended the meeting but spoke on condition of anonymity.

Pichai’s trip to Capitol Hill comes in anticipation of his appearance at a hearing later this fall, where lawmakers stressed they would press him not only on charges of censorship but other issues facing the company, including the privacy protections it affords users and its ambitions to relaunch its search engine in heavily censored China.