Leftist groups in Bolivia threatened Friday to renew their protests after Congress approved legislation that would raise taxes on petroleum and gas production while spokesmen for President Carlos Mesa said he would study the bill carefully before deciding whether to sign or veto it. dpa reported The opposing groups said the bill, approved by the lower house of Congress Thursday by a 59-48 vote and three blank votes, did not go far enough while the president has said the legislation would harm foreign investment in energy and would harm Bolivia's interests. The bill, which was also approved by the Senate last week, establishes a 32-per-cent tax and keeps 18-per-cent royalties on petroleum and gas firms, most of which are foreign-owned. It also obliges current contracts to be renegotiated in the country with the second-largest gas reserves in South America as well as one of the lowest royalty rates in the world. The issue pits two opposing groups against one another. Indigenous groups lead the opposition and want more of Bolivia's natural wealth to remain in Bolivia while business leads the other camp, seeking more investment in the country where 64 per cent of population living in poverty. --More 0107 Local Time 2207 GMT