The new host of the "The Daily Show" Trevor Noah faced mounting criticism on Tuesday after the emergence of several past Twitter posts accused of being anti-Semitic, AFP reported.
The 31-year-old South African comedian, largely unknown in the United States, was named by Comedy Central television on Monday as the successor to long-serving "Daily Show" star Jon Stewart.
A firestorm of controversy raged around Noah's appointment after the emergence of a series of jokes made on the comic's Twitter timeline.
In one post from 2009, Noah appears to take aim at the Holocaust, tweeting to followers: "Almost bumped a Jewish kid crossing the road. He didn't look b4 crossing but I still would hav [sic] felt so bad in my german [sic] car!"
Another post appeared to be a barb at Israel's foreign policy, saying, "South Africans know how to recycle like israel [sic] knows how to be peaceful."
Responding to the past tweets, the Anti-Defamation League (ADL) wished Noah success in his new role at "The Daily Show", but said some of the comedian's past tweets played into "classic anti-Semitic stereotypes."
"We need humor -- perhaps now more than ever -- and we hope that he will build on Jon Stewart's great legacy," ADL national director Abraham Foxman said in a statement, quoted by AFP.
"We hope that he will not cross the line from legitimate satire into offensiveness with jokes calling up anti-Semitic stereotypes and misogyny," Foxman added, urging Noah to avoid "bigoted jokes" targeting Jews, other minorities and women.
Comedy Central appeared unmoved by criticism it branded as "unfair", offering staunch support to Noah in a statement.
"Like many comedians, Trevor Noah pushes boundaries; he is provocative and spares no one, himself included," the network said, according to AFP.
"To judge him or his comedy based on a handful of jokes is unfair. Trevor is a talented comedian with a bright future at Comedy Central," it added.