 The government of Tajikistan asked Russia on 15 May 2004 to begin withdrawing some of its 20,000 troops from Tajikistan's border with Afghanistan.The withdrawal of troops concerned the US government because the troop presence helped prevent cross-border drug trafficking.On 28 May 2004, President Karimov and Tajik President Imomali Rakhmonov said drug trafficking in Afghanistan needed to be solved by forces within the country; drug traffickers were estimated to make $3.5 billion annually.