WASHINGTON (Reuters) - U.S. senators said on Sunday the White House has not been forthcoming with details about the military’s presence in Niger after the deaths of four soldiers there earlier this month and they want more answers on U.S. operations in the west African country.

Republican Senator Lindsey Graham and Democratic Senate leader Chuck Schumer said in separate interviews that they support Republican Senator John McCain’s effort to get answers from the Pentagon on the ambush and more broadly on the U.S. fight against ISIS in Niger.

Graham and Schumer said they had been unaware of the large U.S. presence in the country and said Congress needs more information on what could become a long and open-ended involvement.

“I didn’t know there was 1,000 troops in Niger,” Graham said on NBC’s Meet the Press. “This is an endless war without boundaries and no limitation on time and geography,” he added. “You’ve got to tell us more and he [McCain] is right to say that.”

Defense Secretary Jim Mattis told Graham and McCain, who serves as chairman of the Senate Armed Services Committee, on Friday that the military is shifting its counter-terrorism strategy to focus more on Africa and expanding the ability to use force against suspected terrorists.

The attack earlier this month, which U.S. officials suspect was carried out by a local Islamic State affiliate, has thrown a spotlight on the U.S. counter-terrorism mission in Niger, which has about 800 U.S. troops.

U.S. President Donald Trump drew attention to the ambush after sparring last week with Democratic Congresswoman Frederica Wilson, who criticized the president for what she said were insensitive remarks to the widow of one of the fallen soldiers.

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Democrat Schumer said on the same program on Sunday that he, like Graham, had also been unaware of the large presence of U.S. troops in Niger and is also awaiting more answers from the military this week.

He said Congress may need to re-examine the current authorization for what he said could be a long, open-ended involvement in the country and region.

“We need to look at this carefully. This is a brave new world. There are no set battle plans,” he said, adding that Congress currently authorizes action as part of the authorization of military use that has been in place for 16 years since the September 11 terror attacks on the United States.

“I would be for re-examining this. There is no easy answer but we need to look at it. The answer we have now is not adequate,” he said.