For the second night in a row, ABC “World News” and NBC “Nightly News” will broadcast for an hour as the networks continue to feature extended coverage of the earthquake in Haiti. (Update: CBS tells us “Evening News” will also be extended to an hour.)

NBC’s Brian Williams and CBS’ Katie Couric anchored their respective programs last night from Port-au-Prince, though both were struggled with serious technical limitations. Diane Sawyer is set to anchor “World News” from Haiti this evening after arriving from Afghanistan with reporting from .

ABC is also planning a “20/20″ primetime special titled “Earthquake Haiti: Race to Save a Country” anchored by Sawyer, George Stephanopoulos and Elizabeth Vargas to air tonight at 8pm. Chris Cuomo will report from “Little Haiti” in Miami. On Friday, Vargas and Cuomo will focus the entire “20/20″ broadcast on the earthquake.

In addition, “Nightline” will again devote tonight’s entire show to the situation in Haiti.