President Jacob Zuma's decision to assign three of his ministers to help the KwaZulu-Natal government and the police quell the latest surge of xenophobic violence in the province is overdue. In recent days hundreds of foreigners have had to flee their homes and several have been killed in a surge of violence, mainly in townships in the Durban area. Shops and homes have been attacked and looted, and the refugees, who have been warned by locals not to return to their homes, are being housed in transit camps.Outrages of this sort are extremely dangerous and the terrible events of 2008, in which more than 60 people were killed in xenophobic rampages, simply cannot be allowed to recur.Violence against foreigners has become depressingly familiar in townships since the end of apartheid as people, many of them struggling on the margins, compete for jobs or to attract spaza shop customers.Some of the hatred is being engineered by criminals, and by business rivals seemingly unable to compete with their foreign counterparts.But it is undeniable that many South Africans - including the police - are suspicious of foreigners and far too ready to brand them all as criminals or cast aspersions on their business practices.And, as we saw in the aftermath of the xenophobic violence in January, political leaders are not immune to this sort of stereotyping. Small Business Development Minister Lindiwe Xulu did herself no favours when she said foreign shopkeepers should share their trade secrets with locals.Zulu king Goodwill Zwelithini has been blamed in some quarters for the Durban attacks after suggesting that foreigners should pack their bags and leave. To his credit, he denounced the violence last week, saying the Africans being attacked were his people too.As we collectively strive to uproot the scourge of xenophobia our leaders need to choose their words extremely carefully...