PYONGYANG - Syria's ambassador to North Korea denounced US aggression and "history of interventions" on Monday and said sending a "message" to North Korea with an attack on a Syrian airfield was irresponsible.North Korea has conducted several missile and nuclear tests in defiance of UN sanctions and has said it has developed a missile that can strike the US mainland. Its latest missile test on Sunday failed a few seconds after launch.US Vice President Mike Pence put North Korea on notice on Monday, warning that recent US strikes in Syria, one of North Korea's few close allies, and Afghanistan showed that the resolve of President Donald Trump should not be tested.The US Navy this month struck a Syrian airfield with 59 Tomahawk missiles after a chemical weapons attack. On Thursday, the US military said it had dropped the largest non-nuclear device it had unleashed in combat on a network of caves and tunnels used by Islamic State in Afghanistan.Syrian Ambassador to North Korea Tammam Sulaiman said the United States was wrong to send messages with attacks on other countries."Whatever they do, this is clear aggression. If they want to mention this they ought to do this as a message or whatever, it has no sense to talk about this," he told Reuters in English."Because what is sense is to see whether the US is really serious in finding solutions, whether in Syria or Korea. If they want to keep sending messages, then you are not talking with a responsible state or a responsible administration. It is not about giving messages, it is about taking a position."