A trio of leading US senators warned Egypt that the risk of a "disastrous” rupture in ties had "rarely been greater” amid an escalating row over the planned trial of US pro-democracy activists.Echoed by a bipartisan chorus of anger from US lawmakers, Republican senators John McCain and Kelly Ayotte, joined by independent Joe Lieberman, also warned that US congressional "support for Egypt -- including continued financial assistance -- is in jeopardy.”Washington currently provides some $1.3 billion a year in aid to its key Arab ally -- one of the biggest aid packages offered to any nation."The current crisis with the Egyptian government has escalated to such a level that it now threatens our long-standing partnership,” the senators wrote in a joint statement."There are committed opponents of the United States and the US-Egypt relationship within the government in Cairo who are exacerbating tensions and inflaming public opinion in order to advance a narrow political agenda,” they said."A rupture in relations would be disastrous, and the risks of such an outcome have rarely been greater,” the senators added.Egyptian justices have announced plans to put dozens of pro-democracy activists, including 19 Americans, on trial over alleged illegal funding to foreign aid groups -- a move that has clearly left US lawmakers seething.The row has led some to openly question the crucial Egypt-US partnership that has anchored America’s Middle East policy for a generation and helped keep the peace between Israel and its Arab neighbors.Democrat John Kerry, influential chairman of the Senate Foreign Relations Committee, berated Egypt’s leaders for what he said was a "slap in the face to Americans who have supported Egypt for decades and to Egyptian individuals and NGOs who have put their futures on the line for a more democratic Egypt.”