Iran has warned that if the United States attacks it, Tehran will retaliate against US bases on the soil of US allies in the Middle East, a senior Iranian official told Reuters on Wednesday, after US President Donald Trump threatened to attack Iran in support of protesters. The death toll in the ongoing protests in Iran has risen to about 2,600, according to a rights group. The protests are seen as one of the biggest challenges to the country's religious leadership since the Islamic Revolution in 1979.