The attack came Monday hours after Abdullah bowed to popular demands for electing a prime minister from a parliamentary majority, replacing the current method of appointing the Cabinet.
The security official said the king was not hurt.
He said a crowd of young people attacked the motorcade twice in two different areas in Tafila, 200 kilometers (125 miles) south of the Jordanian capital.
Abdullah was on a fact-finding trip to inspect infrastructure projects and hear his subjects' demands.
The official insisted on anonymity because he is not allowed to comment on the king's affairs.
