The U.S. State Department contacted the social networking service Twitter over the weekend to urge it to delay a planned upgrade that could have cut daytime service to Iranians, a U.S. official said on Tuesday.

We highlighted to them that this was an important form of communication, said the official of the conversation the department had with Twitter at the time of the disputed Iranian election. He declined further details.

(Reporting by Sue Pleming, Editing by Sandra Maler)