PARIS, Oct 29 (Reuters) - AXA (AXAF.PA), France"s biggest insurer, said on Friday it would tighten its policy regarding investing in and insuring the oil and gas sector, as pressure builds on finance to help curtail new production. The announcement, which comes before global leaders meet for the COP26 climate summit in Scotland, follows growing calls from bodies including the United Nations for new fossil fuel projects to be stopped in order to help cap global warming. read more AXA said it would stop investing in and underwriting new upstream greenfield oil exploration projects unless they were carried out by companies "with the most far-reaching and credible energy transition plans". This would see it avoid new direct investments in listed equities and corporate bonds in developed markets in oil and gas companies operating in upstream, oilfield services, downstream subsectors and most midstream players, it said.From 2023, AXA would begin to factor the policy into its underwriting business of new insurance coverage on new upstream greenfield oil exploration projects, it added. “The climate emergency requires us to step up our actions and support the transition towards a low-carbon economy," said AXA Chief Executive Thomas Buberl."Going forward, AXA is determined to focus its support only on actors with the most far-reaching and credible transition strategies.” It also increased its target for "green" investments to 26 billion euros ($30.3 billion) by 2023, from 24 billion announced at the end of 2020. Peter Bosshard, coordinator of the Insure Our Future campaign, said: "In principle it"s positive that the insurance industry is now finally starting to shift away from oil and gas. "But self-proclaimed climate leaders need to follow the science and rule out all support for the expansion of fossil fuel projects right away," Bosshard said. ($1 = 0.8589 euros)