CALIFORNIA, United States: In the United States, Sunni-Shia leaders are trying to get American Muslims to focus on common problems.

Leaders from both traditions have launched "Intra-faith Code of Honor" campaigns in three cities with major Muslim populations.

So far, 20 Sunni and Shia leaders in Southern California have signed the first such code. The document denounces "takfir" — the labeling of another Muslim as a nonbeliever — forbids hateful speech about revered figures and urges debates at the scholarly level, not the street level.

Similar agreements are expected to be completed this month in Detroit and Washington, D.C.

Hojjatol-Islam Hassan Qazwini of the Islamic Center of America in Dearborn, Mich., the largest mosque in North America, said Sunnis and Shias get along.

"Shias and Sunnis need to work together so we can face our joint challenges," Qazwini said.