COLOMBO (AFP) - The United States said Saturday it remained "deeply concerned" about alleged Sri Lankan war crimes as it distanced itself from a junior US military officer who questioned the credibility of the accusations against the island. The US government, along with other Western nations, rejected an invitation to attend a seminar hosted by Sri Lanka earlier in the week to showcase its success in crushing Tamil separatists by May 2009. However, the US defence attache in Colombo, Lieutenant Colonel Lawrence Smith, attended the seminar as an "observer" and his remarks there were his own "opinion", the US state department said in a statement received in Colombo.