A British cabinet minister has quit over the government's policy on Gaza.

Baroness Sayeeda Warsi, who is of Pakistani origin, announced her resignation on Twitter, saying: "With deep regret, I have this morning written to the Prime Minister and tendered my resignation. I can no longer support the Govt policy on #Gaza."

She later posted the full letter of resignation to the social networking site.

"My view has been that our policy in relation to the Middle East Peace Process generally, but more recently our approach and language during the current crisis in Gaza is morally indefensible," the letter said.

Baroness Warsi, who is Senior Minister of State at the Foreign and Commonwealth Office, and Minister for Faith and Communities, was the first Muslim woman to serve in the British cabinet.

David Cameron, the British prime minister, has come under increasing pressure for his policy on Gaza.

On July 10, the third day of the offensive, Cameron "strongly condemned the appalling attacks being carried out by Hamas against Israeli civilians...and underlined Israel’s right to defend itself from them".

The comment drew a backlash from rival politicians and members of the public.

Earlier this week, Labour leader Ed Miliband launched a strongly worded attack on Cameron's Gaza policy to date, accusing his political rival of a failure in leadership and criticising his "silence on the killing of innocent Palestinians".

As the civilian death toll in Gaza rose to around 1,800, Cameron, along with the United States, finally on Monday openly criticised a recent strike near a UN school, warning Israel that targeting civilians was "wrong and illegal".