U.S. officials report that Netanyahu the Israeli Prime Minister has formally asked the Defense Secretary Panetta to approve the sale of GBU-28 bunker buster bombs to Israel. These bombs could be used in an attack on Iran.
In added pressures President Obama according to reports told Panetta to work directly with Israeli officials and to consider the request favorably. The aim is to send the weapons as soon as possible.
Along with the refueling aircraft, also requested, the bunker bombs would be key to any Israeli attack on Iran. Many Iranian nuclear facilities are highly reinforced.
Israel did receive some of the bombs in 2009 but receiving more has not just practical value but also is symbolic in that Obama can be seen as on side with the hawkish Netanyahu government.
Although Obama has so far opted for diplomacy and severe sanctions he has also said that he will not allow Iran to have nuclear weapons. In particular he rejected the idea of containment of a nuclear Iran. This certainly keeps an attack on the table. Sending bunker-bombs is also a sign of support for an attack on Iran.
At present however Iran has agreed to negotiations and also has agreed to let IAEA inspectors in to a secret military facility. For more see this article.