The assertion implies that Britain will not contribute weapons to Kurdish Peshmerga or Iraqi security forces battling advances by the Islamic State.
Last week, Cameron expressed support for U.S. President Barack Obama's decision to authorize targeted airstrikes against Islamic State militants, and committed to providing aid -- not arms -- to Iraq.
Cameron's office issued a statement on Tuesday stating "Our focus remains the humanitarian situation, particularly those trapped on Mount Sinjar."
"Three U.K aid drops have now taken place, with two C-130s delivering 3,180 re-usable water containers, filled with a total of 15,900 litres of clean water, and 816 solar lanterns overnight. We will continue with these deliveries. And, as part of our efforts to alleviate humanitarian suffering in Iraq, we are sending a small number of Chinook helicopters to the region for use if we decide we need further humanitarian relief options."
While Cameron acknowledged that Britain "also agreed to transport from other contributing states some critical military re-supplies for the Kurdish forces," there was no mention of U.K. military aid contributions.
Amid mounting public pressure for Britain to provide military support, Cameron cut short his vacation to return to London for a briefing on the situation in Iraq. His office tweeted on Wednesday, "The PM is now back in the U.K. and will chair the routine daily COBR at 13:00 for the latest updates on the situation in Iraq."
The PM is now back in the UK and will chair the routine daily COBR at 13:00 for latest updates on situation in Iraq— UK Prime Minister (@Number10gov) August 13, 2014
Some in Parliament, including Conservative Liam Fox who was previously Defense Secretary, have called for Britain to join U.S. airstrikes against Islamic State targets.
"The idea that this is not our problem is wishful thinking at best, and catastrophic complacency at worst. The US government has made a belated, but welcome, decision to use American air power to hit Isis bases. We should be willing to do the same if asked," Fox wrote in the Daily Mail.
"Sending humanitarian aid is right," Fox added, "but if we are leaving the vulnerable unprotected from the military terror of the ISIS forces then our help is superficial."