Iran's Revolutionary Guard Corps (IRGC) said on Tuesday that it reserved the "legitimate and definite" right to retaliate against any ceasefire violations by the United States, adding that its air defence units had shot down a US MQ-9 drone.US and Iran are working towards a peace agreement even as tensions escalate. (AFP)According to the reports in Iranian media quoted by Reuters, the IRGC also claimed to have fired at a fighter jet that had entered Iranian airspace. This comes after the US said it conducted fresh “self-defence strikes” on Iran.Iran's Supreme Leader, Mojtaba Khamenei, also released a statement on Tuesday, saying that regional countries would no longer be shields for US bases.He said it in a written statement carried by state television."What is certain in this regard is that the hands of time will not turn backwards, and the nations and lands of the region will no longer serve as shields for American bases," said Khamenei, who has not appeared in public since he took office in March, in a message marking the Eid al-Adha holiday.He said the United States was losing influence in the region, "moving further and further away from its former status with each passing day".Escalation in tensionsThe escalated tensions come hours after the US said it struck Iranian missile sites and boats “that were laying mines”. The statement issued by the US Central Command did not give further details."US forces conducted self-defence strikes in southern Iran today to protect our troops from threats posed by Iranian forces," Tim Hawkins, a US CENTCOM spokesperson, said in a statement.The strikes came as top Iranian negotiators arrived in the Qatari capital of Doha for the latest round of talks to end the months-long conflict, which had prompted Iran to blockade the Strait of Hormuz, a crucial route for global energy exports, sending prices soaring and the global economy into a tailspin.Iran's state-run broadcaster IRIB reported several loud explosions were heard in the vicinity of Bandar Abbas at around midnight local time (2030 GMT Monday).It added that the situation in the southern port city was normal and local authorities were investigating the cause of the blasts.The US-Iran peace dealThe two sides have been negotiating a deal to extend the ceasefire for about 2 months, with Washington lifting its blockade and Tehran reopening Hormuz. Still, sticking points remain, with Tehran saying it must be able to manage traffic through the chokepoint, something the US, Arab states and Europe maintain cannot be allowed.US Secretary of State Marco Rubio told reporters in India on Tuesday that negotiations will still “take a few days” as both sides discuss language in an initial document. President Donald Trump posted that the talks were “proceeding nicely,” while also threatening more attacks if they were unsuccessful.In a separate post, Trump said Tehran’s enriched uranium would preferably be destroyed in Iran, although the material could also be turned over to the US.Washington has cited the Islamic Republic’s nuclear program as a major reason for embarking on the conflict with Israel, maintaining that Tehran poses a threat as it wants to develop nuclear weapons. Meanwhile, Iran denies it.