WARREN (AP) — President Joe Biden chatted with a friendly union crowd inside a United Auto Workers hall in Michigan on Thursday as pro-Palestinian demonstrators held back by police with riot shields voiced their anger nearby at the president’s full-throated support for Israel in its war with Hamas.

The tension highlighted the challenges ahead for Biden in holding on to this critical battleground state in November over likely rival Donald Trump, and underscored the Democrats’ concerns about flagging enthusiasm among voters who have been key to their coalition.

Biden’s visit with autoworkers making phone bank calls for him ahead of the state’s Democratic primary came just days after union President Shawn Fain announced their endorsement of him. Fain praised Biden’s ties to the working class, saying, “We know who’s been there for labor and who wasn’t,” adding that the union’s mission now is to “keep Joe Biden as our president.”

Biden, who joined striking workers on the picket line last year, replied, “Supporting you is the easiest thing I’ve ever done.”

However, Biden’s Michigan schedule did not include any meetings with Arab Americans, adding to increasing frustration over his support of Israel in its war with Hamas as the Palestinian death toll has mounted.

“Why not have a meaningful conversation for how you change course with a community that has first-hand accounts of what it’s like to live in the countries where your decision-making is unfolding?” said Abdullah Hammoud, the mayor of Dearborn, one of the largest Arab American communities in the nation.

Despite the White House offering no advance details about Biden’s planned meeting, close to 200 pro-Palestinian demonstrators were waiting for Biden near the UAW Region 1 building in Warren ahead of his event there. The president’s motorcade bypassed them using side streets.

Protesters chanted “Hey Biden, what do you say? We won’t vote on Election Day” as well as pro-Palestinian slogans, including “Free, free Palestine.”

Amir Naddaf, 34, traveled with friends from Ann Arbor to protest the president’s UAW event after having supported Biden in the 2020 election

“We came here to send a clear message to the administration that they’re not welcome in Michigan,” said Naddaf.

Dozens of riot gear-clad police officers and an armored vehicle kept the protesters from approaching the union hall.

More than 26,000 Palestinians, mostly women and minors, have been killed in Gaza since Hamas attacked Israel on Oct. 7, according to the Health Ministry in the Hamas-ruled territory. Hamas killed more than 1,200 people and kidnapped about 250 more, mostly civilians, in the attack.

Michigan has shifted increasingly Democratic in recent years, with the party controlling all levels of state government for the first time in four decades. Biden is looking to build on that power as he seeks reelection and the state’s critical 15 electoral votes.

The president faces no serious challenge in the primary, but his campaign is trying to build energy for the tougher fight to come in the fall. Michigan was part of the so-called blue wall of three states — with Wisconsin and Pennsylvania — that Biden returned to the Democratic column when he won the White House in 2020.