WASHINGTON — Newly planned talks with Tehran are the “last chance” for Iran to forge a deal and avoid an escalation of US strikes on the country, President Donald Trump said Monday. “This the last chance for them to sign a good document,” Trump told reporters. Earlier Monday, Trump had criticized Iran on social media as being “unbelievably duplicitous.” Trump said whether “Iran wants to admit it or not, we are, in fact, talking” about preventing Iran from developing nuclear weapons. “I want to give them every last chance before decapitation,” Trump said.