CAIRO, May 26 (Xinhua) -- The Arab League on Thursday warned against a planned march by Jewish nationalists in East Jerusalem. "The provocative flag march will jeopardize security, stability, and efforts of mitigating the escalating tensions," said Saeed Abu Ali, Arab League assistant secretary-general for Palestine affairs and occupied Arab territories. The controversial "flag march" is due to take place on Sunday to mark Jerusalem Day, which commemorates the unification of the city after Israel annexed East Jerusalem in 1967. Condemning "in the strongest terms" the Israeli decision to allow the flag march to pass through Islamic neighborhoods in East...