Republican nominee Mitt Romney paid tribute on Thursday to four American diplomats killed in Libya, and while he steered clear of President Barack Obama’s handling of the crisis he said US power was vital in the Middle East.

Romney sparked a furor late Tuesday and Wednesday when he offered quick and blunt criticism of steps the Obama administration took to try and tamp down a rapidly escalating protest in Cairo, Egypt, amid swirling regional violence that ended up claiming the life of the US Ambassador to Libya.

“I know that we have heavy hearts across America today,” Romney said while campaigning in swing state Virginia, near the US capital.

“We’ve lost four of our diplomats across the world, we’re thinking about their families and those that they’ve left behind.”

But while calling the deaths “a tragedy,” Romney did not repeat some of his earlier accusations that the Obama administration was apologising for American values and sympathising with the protesters.

Instead he shifted to one of his broader themes on the campaign trail, that the United States under Obama is no longer projecting the military might and strength it did in the past.

“As we watch the world today, sometimes it seems that we’re at the mercy of events instead of shaping events, and a strong America is essential to shape events,” Romney told about 2,700 supporters in a suburban park.

“The world needs American leadership. The Middle East needs American leadership and I intend to be a President that provides the leadership that America respects and will keep us admired throughout the world.”

Romney, a former Governor of Massachusetts, hammered Obama for trimming the military budget by nearly half a trillion dollars over the next decade, given that defense spending will increase at a slower rate than it did under the last Republican President, George W Bush.

The White House hopeful also sought to blame the President for another half trillion in automatic defense cuts that will kick in next January if Congress does not act, though both Republicans and Democrats agreed to that reduction.