WASHINGTON (AP) The United States expressed concern Wednesday about tens of thousands of Palestinians pouring into Egypt from the Gaza Strip across a broken security barrier at the border of the small territory run by Hamas militants.

"We are concerned about that situation and frankly I know the Egyptians are as well," State Department deputy spokesman Tom Casey said.

David Welch, the assistant secretary of state for the Middle East, and American diplomats in Cairo have talked to Egyptian authorities about the situation, Casey said, but he didn't offer details. He said the Egyptians take border security seriously and that he has no indication the situation has affected Israeli-Palestinian relations for now.

"I'm not going to try and speak for Egypt, give public recommendations to the Egyptian government on how to control their sovereign border," Casey said, adding that the United States is available to offer advice or support.

The Palestinian exodus was a protest against the closure of the impoverished Palestinian territory imposed last week by Israel. Israel controls most of Gaza's land borders, while Egypt shares a small border with the territory around the market town of Rafah. Egypt generally keeps its border with Gaza under tight control, although Israel accuses Egypt of looking the other way when it comes to smuggling operations.

The border crossings put Israel and the United States in an awkward spot as President Bush pushes new Israeli-Palestinian peace talks. Egypt is one of only two Arab states to make peace with Israel, and holds a historic role as Arab host and broker for peace talks.

Israel has come under international criticism for sealing off Gaza as a pressure tactic against Hamas militants who took over the strip in June, but is reluctant to criticize Egypt for allowing Palestinians free passage Wednesday.

The United States does not want to publicly criticize either Israel or Egypt. It aimed instead at Hamas, the militant political and military organization pledged to Israel's destruction. Israel and the United States are backing Palestinian President Mahmoud Abbas, of the rival Fatah Party, in a bitter fight between the Palestinian factions.

"The Palestinians living in Gaza are living under chaos because of Hamas, and the blame has to be placed fully at their feet," White House press secretary Dana Perino said Wednesday.

Jubilant men and women crossed unhindered over the toppled corrugated metal along sections of the barrier in Rafah, carrying goats, chickens and crates of Coca-Cola. Some brought back televisions, car tires and cigarettes and one man even bought a motorcycle. Vendors sold soft drinks and baked goods to the crowds.

They were stocking up on goods made scarce by the Israeli blockade and within hours, shops on the Egyptian side of Rafah had run out of stock.

Earlier Wednesday, Secretary of State Condoleezza Rice offered a muted response, saying in Switzerland that the U.S. wants to see stability in the region, but that "most importantly both the security concerns of Israel and the humanitarian concerns of Gazans be met."