Although there was no recognizable nationalist movement among the indigenous population until 1908, Dutch authorities feared that nationalist sentiments would spread with the growth of ethnically mixed associations, known as "kongsi". In 1911, some Javanese members of the Kong Sing association in Surakarta broke away and clashed with the ethnic Chinese. This incident led to the creation of Sarekat Islam, the first organized popular nationalist movement in the Indies. Indigenous groups saw the Chinese nationalist sentiment as "haughty", leading to mutual antagonism. The anti-Chinese sentiment spread throughout Java in 1918 and led to violent attacks orchestrated by members of Sarekat Islam on the ethnic Chinese in Kudus. Following this incident, the left-wing Chinese nationalist daily "Sin Po" called on both sides to work together to improve living conditions because it considered most ethnic Chinese, like most of the indigenous population, to be poor.