Afghanistan's foreign minister warned government colleagues Monday to be cautious and conduct 'business-like' relations with overseas diplomats after leaked US cables criticised the president as weak. Zalmai Rassoul said the cables unveiled online last week by whistleblower WikiLeaks had undermined trust across the world, including in his war-torn country. 'WikiLeaks has caused trouble for diplomatic relations all over the world,' Rassoul told a press conference in Kabul. 'This is a vital issue, particularly for us... we must be extraordinarily careful in our contacts with foreigners and embassies,' he said. 'We must be careful and be... business-like.' At the weekend Afghan President Hamid Karzai said he doubted the credibility of the leaked documents, saying they were part of a campaign to 'defame' his Western-backed administration. In one cable, US ambassador Karl Eikenberry portrayed Karzai as 'paranoid and weak' and 'unfamiliar with the basics of nation building'. In another document, US diplomats said one of Karzai's deputies had transported 52 million dollars out of the country in suitcases, a claim which Rassoul dismissed as untrue. 