Obama blasts Trump's 'chaos and cruelty' while campaigning for Democrats

 Former US President Barack Obama speaks as he campaigns alongside Michigan Senate candidate Abdul El-Sayed in Detroit. [Bill Pugliano, AFP]

Former US president Barack Obama delivered scathing criticisms of current leader Donald Trump at rallies Saturday in Ohio and Michigan to support Democratic candidates ahead of the November 3 midterm elections.

Democrats are attempting to wrest back control of one or both chambers of the US Congress, which are currently controlled by Trump's Republican party.

Obama remains popular with the Democratic base, which he wants to leverage to support his party's candidates.

In both states, the 65-year-old former president blamed the Trump administration for the rising cost of living, a top voter concern.

"The current president chose to make a series of bad decisions," Obama said in Cleveland, Ohio, where he rallied in support of former Democratic senator Sherrod Brown.

"Most importantly, he decided to start an unnecessary war that nobody asked for."

The war on Iran has sent oil prices soaring as Tehran effectively blocked the Strait of Hormuz after being attacked.

"After two years of chaos and cruelty and corruption and incompetence, the likes of which we have not seen in the modern era, you get a chance to say, 'Enough is enough,'" Obama declared. "We are voting for change right here in Ohio."

Later, in Michigan, Obama campaigned for Abdul El-Sayed, from the party's left wing, who is in a close race with Republican Mike Rogers for the US Senate.

"Imagine the power duo of Abdul and Elissa," Obama said, referring to the incumbent Democratic Senator Elissa Slotkin, who is not up for election this year.

"You got a Muslim man, you got a Jewish woman fighting for you in the United States Senate. That's something, Michigan, you can be proud of."

Trump slammed Obama's campaign in Michigan in a post on Truth Social on Sunday, urging voters to choose Rogers.

"Obama was a grossly incompetent President! He paid off Iran with $Billions, and gave them a road to a Nuclear Weapon," Trump said, referring to a 2015 deal negotiated under Obama that offered Iran sanctions relief in return for drastically scaling back its nuclear work.