WASHINGTON - The United States is pressing for a ceasefire in the Gaza Strip that would include three main elements, including a halt to Hamas' rocket attacks on Israel, the State Department said Monday.

Secretary of State Condoleezza Rice has held telephone conversations with numerous foreign leaders in pursuit of such a ceasefire agreement, her chief spokesman, Sean McCormack said, adding that much detailed work remains to be done.

"We're doing a lot of work on these three elements," McCormack said, adding that the goal is to establish a halt to the violence that would meet Rice's standard of being durable and sustainable.

In addition to halting the rocket fire from Gaza, the proposed ceasefire would include an arrangement for reopening crossing points on the border with Israel, McCormack said. The rocket attacks were sparked by Israel's siege of Gaza.

The third element, which he mentioned only in general terms, would entail addressing the issue of tunnels into Gaza from Egypt through which Hamas has smuggled a variety of materials, including arms.

The State Department has withheld direct comment on the Israel ground thrust into Gaza, which began Saturday. Pressed for comment Monday, McCormack said, "Every sovereign state has to decide for itself how best to defend itself." He also reiterated the administration's concern about the conflict's impact on civilians.

The Gaza crisis prompted Rice to cancel a long-planned trip to China this week. Rice has been making a stream of phone calls to allies in the Middle East and Europe in hopes of fostering a ceasefire in Gaza, but McCormack said Monday that she has no current plans to visit the region as part of that effort.

Israel's 10-day aerial bombardment of Gaza and the start of the ground offensive Saturday against Hamas have drawn condemnation across the Muslim and Arab world and news coverage of the invasion has dominated Arab satellite television stations.

McCormack said Rice last spoke to her designated successor, Hillary Clinton, about the Gaza situation last Thursday.