A Downing Street spokesperson said:
The Prime Minister regrets that Baroness Warsi has decided to stand down and is grateful for the excellent work that she has done both as a Minister and in Opposition.
Our policy has always been consistently clear - the situation in Gaza is intolerable and we've urged both sides to agree to an immediate and unconditional ceasefire.
More top news
Prince Albert II and Princess Charlene of Monaco are expecting twins next month and the first one born will be the prince's royal heir.
Train company First Great Western is aiming to reunite lost cuddly toys with their owners.
A grey start to the weekend with patchy rain for Scotland and eastern England.