Barack Obama says 'the window is closing' for a peace deal between Israel and Palestine.
More than 70 heads of state will be arriving in South Africa for the FNB memorial service.
The Senate is scheduled to meet at noon on Wednesday.
President Barack Obama on Wednesday scaled down a long-planned trip to Asia.
There are fears that more South Africans might be among those who are still trapped inside the mall.
Obama has asked the US Congress to approve military action, France has said it is ready to support.