Two out of three Americans believe US President Donald Trump has failed to clearly explain why the country entered the war against Iran, according to a new poll that also showed a slight rise in his approval rating from the lowest point of his current term. Around 36% of Americans said they approved of Trump's performance, up by two percentage points from a late April Reuters/Ipsos poll. (REUTERS)The conflict has led to nearly a 50% rise in petrol prices across the US after Iran shut down a fifth of global oil trade. Notably, Tehran has continued to keep the Strait of Hormuz closed despite attempts by US warships to restore oil tanker movement through the key route. Follow US-Iran war live updates here. Poll shows Americans unconvinced by Trump's explanation on Iran warThe Reuters/Ipsos poll, completed on Monday, revealed growing concern over rising fuel prices. It also suggested that many voters blame Trump's Republican allies, who are preparing to defend their congressional majorities in the November midterm elections. More than two months after the conflict started on February 28 with a joint US-Israeli bombing campaign, nearly 66% of respondents, including one in three Republicans and almost all Democrats, said Trump had not "clearly explained the goals of US military involvement in Iran,” the poll showed, as per news agency Reuters. Around 36% of Americans said they approved of Trump's performance, up by two percentage points from a late April Reuters/Ipsos poll that placed his approval rating at 34%, the lowest level of his current presidency. The latest poll had a margin of error of three percentage points in either direction. Household expenses hit, worries rise over gas pricesAbout 63% of Americans said recent increases in petrol prices had affected their household finances, up from 55% in a Reuters/Ipsos poll carried out between March 17 and 19. Three out of four Americans, including half of Republican voters, said the Trump administration carried at least some responsibility for the rise in fuel prices, according to the poll. When asked which political party was more responsible, 65% blamed Republicans, while 27% pointed to Democrats. Four out of five Americans said they expected petrol prices to rise further. The Reuters/Ipsos poll was conducted online and included responses from 1,254 adults across the United States. With inputs from agencies