Chuck Hagel, the US defence secretary, announced the deployment on Tuesday, saying that "this is not a combat boots on the ground kind of operation".
Another defence official, speaking on condition of anonymity, said the extra troops were Marines and special operations forces whose mission was to assess the situation in the Sinjar area and to develop additional humanitarian assistance options beyond current US efforts there. The 130 troops, who are in addition to 250 US military advisers already in Baghdad and Erbil, arrived on Tuesday in the city of Erbil, well east of Sinjar.
They are to work with representatives of the State Department and the US Agency for International Development to prevent potential acts of genocide by the fighters of the so called Islamic State who forced them from their villages, the defence official said. In a separate development, the European Union failed on Tuesday to agree on a joint position on supplying weapons to Iraqi Kurds battling the IS, but has said individual members could send arms in coordination with Baghdad.
Masoud Barzani, the Iraqi Kurdish president, asked the international community on Sunday to provide the Kurds with weapons to help them fight the Islamic State group, whose dramatic push through the north has startled world powers.
"The [ambassadors] noted the urgent request by the Kurdish regional authorities to certain member states for military support and underlined the need to consider this request in close coordination with the Iraqi authorities," a spokesman for Catherine Ashton, the EU foreign policy chief, said.
Diplomats said some EU states opposed sending arms, meaning there was no EU-wide agreement to do so, but that they could not prevent other countries from doing so, if they wished.
Amongst the countries in favour of supplying weapons were France, Italy and the Czech Republic, diplomats said. There was, however, no immediate indication that they were about to do so.