U.S. Rep. Keith Ellison, D-Minn., left and U.S. Rep. Brian Baird, D-Wash., right, take photos of the rubble of the American International school in Beit Lahiya in the northern of Gaza Strip, Thursday. (Elliott Polk (Clickability Client Services) — Associated Press/The Minnesota Star Tribune)

WASHINGTON - Rep. Keith Ellison, one of the first high-level U.S. officials to enter the Gaza Strip in more than three years, said he is haunted by the scenes of destruction from Israel's recent military incursion.

"I have an image of a woman sitting in the rubble of her home burned in my head," the Minnesota Democrat said by cell phone Thursday on his way back to an Israeli checkpoint.

Ellison, who met with Gaza civilians and relief workers for about nine hours Thursday, said he was not there to assign blame for the violence, though he said the civilian devastation he witnessed was hard for him to understand.

Today, he plans to tour the Israeli towns of Sderot and Ashkelon, which have been targets of numerous rocket attacks by Hamas forces in Gaza.

"I've always believed we need to resolve this thing by diplomacy," said Ellison. "I'm even more convinced of that now."

The trip came amid heightened tensions as Israel declared that it would not open the Gaza Strip's border crossings until Hamas insurgents freed a captured Israeli soldier. Ellison's visit did not have the official sanction of the Obama administration, and the U.S. State Department warned him about its security concerns.

For Ellison, the first Muslim elected to Congress, the trip is the latest in a series of visits he has made to the Mideast.

Steve Hunegs, executive director of the Jewish Community Relations Council of Minnesota and the Dakotas, said he is interested in learning how Ellison's trip will shape his views about Israel's conflict with Hamas. "We'll look forward to speaking with him upon his return," Hunegs said.

Kerry visits, too

Separately, Sen. John Kerry, D-Mass., chairman of the Foreign Relations Committee, also toured Gaza on Thursday. "Hamas has to change its policies," he said while visiting the ruins of the American International School in Gaza, which was destroyed by an Israeli air attack in early January. "There is no change in our policy." Kerry entered Gaza after seeing the remains of Palestinian rockets fired at Sderot.

Ellison, who ran in 2006 as a supporter of Israel, said he is no less so now. "I'm a supporter of Israel, but I'm a supporter of the Palestinians, too. One does not preclude the other."

Traveling with Rep. Brian Baird, D-Wash., he saw firsthand the devastation from Israel's Dec. 27 invasion, which was meant to stem the Hamas rocket attacks against Israeli border towns. He said he saw damaged schools, hospitals and factories.

Ellison said he was struck by how little hostility he encountered among Gaza's civilians, some of whom offered him sweet tea along the way. "I was a little reluctant to tell people I am an American congressman, but I experienced no hostility or derision," he said.

Nor, he said, did he hear much criticism of Hamas. "A lot of people said they aren't part of Hamas, and they don't feel responsible for them," he added.

Like Kerry, Ellison and Baird did not meet with Hamas officials. But before entering Gaza, they traveled to the West Bank city of Ramallah to meet Riad Malki, foreign minister of the Palestinian Authority.

In January, Ellison was one of 22 House members who abstained from voting for a congressional resolution backing Israel's right to self-defense in its conflict with Hamas. Though Ellison said he recognizes Israel's right to protect its citizens, he questioned the resolution for making little mention of the human suffering in Gaza.

On Thursday, Ellison called for an easing of the Israeli blockade and for an end to the rocket attacks against Israel.

Staff writer Mitch Anderson and the New York Times contributed to this report. Kevin Diaz • 202-408-2753