Ed Sheeran has opened a solo concert in Philadelphia with comments about Gaza, saying what’s happening is “catastrophic and unjustifiable”, in his first show since the his tour plunged into turmoil.

“My heart has been broken by the scale of devastation and loss of civilians’ lives, of children’s lives,” Sheeran said on Saturday, adding that he wanted his music and shows to be about unity and humanity, not politics.

Outside the stadium a small gathering of chanting protesters greeted concertgoers, waving Palestinian flags and chanting “Free, free Palestine”.

Sheeran’s US Loop Tour has been embroiled in crisis since the rapper Macklemore was removed as opening act on Monday, after the owners of stadiums hosting coming shows objected to his shouting “Free Palestine” on stage in New Jersey earlier this month.

Sheeran, 35, has denied being behind the decision to remove Macklemore, instead blaming the tour promoter.

Four supporting acts subsequently withdrew from the tour, issuing public statements citing their support for Palestinians.

Demonstrators protest outside an Ed Sheeran concert in Philadelphia, Pennsylvania. Photograph: Joe Lamberti/Getty Images

Sheeran has been accused by critics of failing to stand up to the stadium owners – led by billionaire businessman Robert Kraft – and was targeted by boycott calls.

Speaking on stage at the beginning of the concert on Saturday, he said: “I’ve had to take and make difficult decisions, and I am making mistakes and I’m so, so sorry for them.

“I don’t want to disappoint fans, and I’ve never wanted to be an activist musician, but this has put me in the middle of an important and passionate argument about freedom of speech and the most complex political issue on the planet.”

He said the 7 October 2023 attacks on Israel were horrific and he considered what was happening in Gaza now to be “catastrophic and unjustifiable”.

“My heart has been broken by the scale of devastation and loss of civilians’ lives, of children’s lives,” Sheeran said.

Before the show, a small group of pro-Palestinian demonstrators congregated outside the stadium. Hillary Steinberg of Philadelphia said she got tickets a year ago but refunded them to attend the demonstration instead, disappointed that Sheeran had not taken a stand.

“I was, until this week, a big Ed Sheeran fan,” Steinberg said. “I think all art is political, and all music is political, and so this choice – even though he was saying that he wasn’t complicit – is a political choice.”

Student Brandon Ateke also accused Sheeran of “complicity” with Kraft and others in silencing Macklemore.

“I decided to not attend the concert and instead attend the protest to bring light to the genocide going on in Gaza today,” the 18-year-old told Agence France-Presse.

Other fans said they were sticking by the musician.

Kassandra Rivera from Philadelphia said: “Everyone has their own opinion and it’s fine … I came here to have a good time and watch Ed Sheeran.”

Fans arrive at Lincoln Financial Field in Philadelphia, Pennsylvania to see Ed Sheeran. Photograph: Matthew Hatcher/AFP/Getty Images

Dwayne Smith from Canada said: “We’re just here for Ed Sheeran. All politics aside, we just like the music. We are here to support him. It’s not about Palestine or Israel tonight, it’s just about the music for us.”

At a time when a growing number of artists are speaking out against the conflict in Gaza and West Bank settler violence, Sheeran has maintained his apolitical stance.

“I have my personal views on this devastating conflict,” the British performer said on Tuesday on Instagram. “Just because I choose not to speak publicly, it doesn’t mean I don’t have them.”

He also said he “spoke with the venues at length all week to try to build a bridge” before Macklemore was dropped. He insisted he would never willingly let down his fans or abandon the touring crew and others who rely on him to make a living.

With Agence France-Presse, PA Media and the Associated Press