WELLINGTON, Sept. 10 (Xinhua) -- New Zealand Prime Minister John Key's electorate office in west Auckland was attacked early Thursday.

    The Fire Service received calls to the building in Kumeu just after 3 a.m. local time (15:00 GMT Wednesday).

    A small fire erupted after something was thrown through the window. It was quickly extinguished. The fire caused only minor damage.

    Key said he would not speculate on the reasons behind an arson attack at his electorate office in Auckland.

    Key said there had not been any warning or threats beforehand, but it might now be necessary to have extra security there.

    Police said it is too early to comment on whether it was a random attack.

    In 2004, an axe attack was made on the electorate office of former Prime Minister Helen Clark in Auckland.