MOSCOW (Reuters) - Pyongyang does not plan to hold any talks with Washington about its nuclear program, a senior North Korean diplomat said on Friday, declaring that possessing nuclear weapons was a matter of life and death for North Korea, the RIA news agency reported. Tension has soared on the peninsula following a series of weapons tests by North Korea and a string of increasingly bellicose exchanges between U.S. President Donald Trump and North Korean leader Kim Jong Un. Trump, in a speech last month at the United Nations, threatened to  totally destroy  North Korea if necessary to defend itself and allies and called the North s leader a  rocket man  on a suicide mission. Choe Son-hui, director-general of the North American department of North Korea s foreign ministry, told a non-proliferation conference in Moscow Washington would  have to put up  with North Korea s nuclear status, RIA reported.  This is a matter of life and death for us. The current situation deepens our understanding that we need nuclear weapons to repel a potential attack.   We will respond to fire with fire.  Pyongyang would regard any attempts to strangle the country via U.N. Security Council sanctions as an attempt  to declare war . Russian Foreign Minister Sergei Lavrov, addressing the same conference earlier on Friday, urged world powers to get behind a joint Russian-Chinese roadmap for settling the crisis over North Korea s weapons program.  We are convinced that its implementation will promote the lessening of military activity and tension on the Korean peninsula and the forming in Northeastern Asia of a system of equal and indivisible security,  he said.  The plan proposes a moratorium on North Korea s missile and nuclear weapons tests, while South Korea and the United States suspend holding military exercises.  The main task at the current stage is to prevent a military conflict which will inevitably lead to a large-scale humanitarian, economic and ecological catastrophe,  Lavrov said.  All the sides involved should exercise restraint.     