The Polish government has officially told the United States it is interested in opening negotiations on the possibility of hosting a US missile defence site.The Polish Foreign Ministry issued a statement saying it had delivered a formal diplomatic note to the US Embassy in Warsaw -- a formal step that followed expressions of interest by Polish Prime Minister Jaroslaw Kaczynski. The statement said that whatever agreements are eventually reached "should contribute to the strengthening security for Poland, the United States of America and international security."