WASHINGTON -- Congress must decide whether to cut aid to the Palestinian Authority after its leadership joined the International Criminal Court last week, the Obama administration said on Monday."Congress holds a great deal of power in this regard," State Department spokeswoman Jen Psaki told reporters, calling the Palestinian move on New Year's Eve "badly damaging."The secretary of state has the authority to take some steps unilaterally. But "overall, the first step would be Congress," Psaki said.Appropriations law allows for roughly $400 million in aid to be transferred to the PA annually. But that funding is conditional: The PA may not include Hamas, classified as a terrorist organization by the US government; it must continue security cooperation with Israel; and it must refrain from taking action against Israel at the ICC.Palestinian Authority President Mahmoud Abbas signed the Rome Statute of the international court on December 31.Lawyers in the administration are currently reviewing Abbas' actions, several US officials said on Monday, assessing whether any legal wires had been tripped. Psaki said the US continually reviews aid around the world "to ensure it complies with the law."Congress reconvenes this week under Republican control, and discussions are already under way over whether to cut the aid. One source close to the deliberations called the likelihood of a cut a "political reality," noting the language of current US appropriations law, explicitly banning ICC actions.Israel's first response to Abbas' move was to suspend the transfer of tax revenues to the PA. Psaki also criticized the Israeli decision, and said US officials were expressing their concerns privately.US aid and Israeli tax revenue are the two primary sources of funds for the Palestinian Authority. Officials in Ramallah have called Israel's suspension of tax revenue "highway robbery," and warn the PA may dissolve without the funds.Withholding the money "raises tensions," she said. "What we're trying to avoid here is a back and forth, tit for tat."