By Jennifer Rigby, Olivia Kumwenda-Mtambo and Maggie Fick LONDON (Reuters) - Health and humanitarian groups around the world were still uncertain on Wednesday if and how they could resume work after the United States issued a waiver for "life-saving" assistance in President Donald Trump's freeze on U.

Secretary of State Marco Rubio backtracked on Trump’s near-total foreign aid freeze and approved potentially billions of dollars in “life-saving humanitarian assistance.” Many aid groups are still unsure what that means.

Approximately 60 senior staff within USAID have been suspended, leaving the agency without clear leadership, five sources familiar with the internal action told CBS News.