Wahhabi sunni muslims say shias and certain other non-Wahhabi Muslims are infidels.
Quote from http://en.wikipedia.org/wiki/Wahhabi#Destruction_of_Islam.27s_early_historical_sites
Destruction of Islam's early historical sites
Main article: Destruction of sites associated with early Islam
The Wahhabi teachings strongly disapprove of veneration of the historical sites associated with early Islam, on the grounds that only God should be worshipped and that veneration of sites associated with mortals leads to idolatry. Consequently, a significant number of buildings associated with early Islam, historic mosques, mausoleums and other artifacts have been destroyed in Saudi Arabia by the Wahhabi followers from early 1800s through the present day. This practice has proved controversial and has received considerable criticism from the Sunni and Shia Muslims and in the non-Muslim world

Quote from http://en.wikipedia.org/wiki/Wahabbism#Attitudes_towards_Non-Muslims
Attitudes towards Non-Muslims
A study by the NGO Freedom House found Wahhabi publications in a number of mosques in the United States preaching that Muslims should not only "always oppose" infidels "in every way", but "hate them for their religion , for Allah's sake", that democracy "is responsible for all the horrible wars of the 20th century", and that Shia and certain other non-Wahhabi Muslims were INFIDELS

Quote from http://en.wikipedia.org/wiki/Wahhabi
Because they gave themselves the ultimate right to declare people Kuffar (plural of Kafir or infidels), Muhammad ibn Abd-al-Wahhab's followers led an army which occupied Ta’if and Mecca (Makkah). This was followed by massacres of unarmed Muslims (including men, women, and children) and the destruction of many graves and holy sites. Muhammad ibn Abd-al-Wahhab also considered destroying the house where the Prophet Muhammad was born and destroyed Sufi shrines and sacred tombs in Mecca and Medina, including the grave of Prophet Muhammad and his companions, out of fear that it might be worshipped.

Source: http://en.wikipedia.org/wiki/Wahhabi