Egypt says it will take responsibility for its border with the Gaza Strip if Israel withdraws from the territory.
Mubarak (right) has been reluctant to help Israel police Gaza
Egypt's Foreign Minister Ahmed Maher made the pledge to maintain border security during a visit to Cairo by his Israeli counterpart Silvan Shalom.
But he said Egypt would not deploy troops in the Gaza Strip if Israel carried out its disengagement plan.
Mr Shalom's visit is part of a flurry of diplomatic activity prompted by the Israeli proposal to withdraw from Gaza.
It is the highest-level contact between the two countries since Ariel Sharon became Israeli prime minister in 2001.
Mr Shalom said any withdrawal would be co-ordinated with Egypt and the US.
The Israeli foreign minister also had talks with Egyptian President Hosni Mubarak, which he described as "very promising".
Mr Maher said at a joint news conference with Mr Shalom that Egypt would defend its border against any spillover of violence if Israel withdrew from Gaza.
"Every country is responsible for protecting its own border. We will assume this responsibility," he said.
However, he again indicated that Egypt would not get involved in helping to ensure security within Gaza, saying that sending Egyptian troops to Gaza had not been considered.
Earlier, Mr Mubarak said Egypt was not prepared to take on responsibility for Gaza security after a pull-out.
Israeli leaders are also discussing their plan to disengage from the Palestinian territories with a team of US envoys led by Assistant Secretary of State William Burns.
In other diplomatic moves, Mr Sharon is expected to have his first meeting next week with Palestinian Prime Minister Ahmed Qurei.
Israeli Deputy Prime Minister Ehud Olmert said he had a "positive" discussion about the plan with UK Prime Minister Tony Blair during a visit to London on Wednesday.
But Mr Olmert warned Israel's fight against militants would continue regardless of a withdrawal.
"Israel doesn't need tanks [in Gaza], there are other ways," he said, "just as effective as the methods we use today. And if they try to use long-range weapons, we will know how to deal with it."
The BBC's Wyre Davies in Jerusalem says Israel's declaration about its proposed withdrawal from Gaza was initially criticised for being one-sided and for failing to involve the Palestinians.
Many settlers oppose the plan to quit the Gaza Strip
But our correspondent adds that while there are still a number of questions and concerns over the Israeli plan, it is clear that the idea is gathering support and credibility.
Palestinian leader Yasser Arafat said on Thursday he would welcome an Israeli withdrawal from Gaza, but only as a step towards a full withdrawal from occupied Palestinian territory.
In an address to Palestinian lawmakers in Ramallah, Mr Arafat said any withdrawal should be co-ordinated through talks with the Palestinian Authority and be within the Middle East peace plan, known as the roadmap.
Mr Arafat also said he was ready to take over from the Israeli army and to enforce law and order.
Mr Arafat's security adviser, Jibril Rajoub, said Egypt had committed itself to restructuring the Palestinian security services to prepare them for taking over security responsibilities in the Gaza Strip should Israel withdraw.
In an interview with the Palestinian daily al-Ayyam, Mr Rajoub said the pledge was conveyed by Egyptian intelligence chief Omar Suleiman during his talks with Mr Arafat on Wednesday.