Washington, June 24 : Former US Vice President Mike Pence, who has declared his bid for the 2024 presidential election, challenged his Republican Party rivals to support a 15-week national abortion ban. Addressing the Faith & Freedom Coalition's annual conference in Washington D.C. on Friday, Pence said: "Let me say from my heart -- the cause of life is the calling of our time and we must not rest and must not relent until we restore the sanctity of life to the centre of American law in every state in this country." The former Vice President, who has long made his evangelical faith central to his political identity, is one of the few Republican candidates to have spoken unequivocally about his support for such a ban, the BBC reported. He further told the gathering that every Republican candidate for President should support 15 weeks "as a minimum nationwide standard" on abortion. After the US Supreme Court overturned the constitutional right to abortion in the country last June, anti-abortion groups are trying to make a federal ban a key 2024 election issue. Opinion polls have suggested that a majority of Americans back some form of legal abortion access, though public support for the procedure being legal drops notably by the end of the second trimester of a pregnancy. Some Republican candidates are however, wary of backing a 15-week pledge. President Joe Biden, a Democrat, is expected to make abortion a central issue in his re-election campaign. About 25 million women of child-bearing age live in a state with restricted or non-existent abortion services since the Supreme Court overturned Roe v Wade last June. Sensing the political risks, many Republican presidential candidates have skirted the issue of abortion bans. Former President Donald Trump, whose conservative appointments to the Supreme Court paved the way for the US right to abortion being overturned, has backed away from endorsing a specific national ban, the BBC reported. Former South Carolina Governor and UN Ambassador Nikki Haley has called a federal ban impossible. Meanwhile, voters are also split on the issue. A February PRRI poll suggested that 44 per cent of Americans would support a 15-week ban on abortion, while 52 per cent opposed such a law. A federal abortion ban would also have to pass both chambers of Congress and Republican efforts to pass such a law have failed in the past. /IANS