MELBOURNE, April 6 (Reuters) - London copper eased on Friday as the dollar rose, but steadied for a second week as expectations of rising seasonal demand in the second quarter supported prices. FUNDAMENTALS * COPPER: London Metal Exchange copper slipped 0.7 percent to $6,768.50 a tonne by 0740 GMT, paring a 1.4 percent advance from Thursday. Prices were set to climb by half a percent this week, the second such gain in a row. This suggests prices may be settling after logging a 7 percent loss in the first quarter, the biggest downdraft since the fourth quarter of 2015. * TRADE: China warned it would fight back "at any cost" with fresh measures to safeguard its interests if the United States sticks to its protectionist actions, after U.S. President Donald Trump threatened an extra $100 billion in tariffs in a worsening trade dispute between the world's two biggest economies. * SHFE: The Shanghai Futures Exchange is closed for a second day on Friday for the Tomb Sweeping Festival and will reopen on Monday. * TRADE TENSIONS: The United States is willing to negotiate with China on trade, but only if talks are serious, as previous attempts produced little progress, a senior U.S. official told Reuters late on Thursday as trade tensions between the two nations escalated. * DOLLAR: The dollar edged higher on Friday, heading for a second week of gains, as investors cut some bets against the currency before monthly U.S. payrolls data that may signal price pressures are growing in the world's biggest economy. * U.S. ECONOMY: U.S. job growth likely slowed in March as the boost from mild temperatures faded, but the gains were probably more than enough to push the unemployment rate down to 4.0 percent, indicating the labour market continues to tighten. * CONGO: International mining companies have insisted that Democratic Republic of Congo amend portions of a new mining code to respect exemptions they were granted by its predecessor. * BATTERIES: China's securities regulator has approved the 13.1 billion yuan ($1.97 billion) initial public offering of Chinese battery giant Contemporary Amperex Technology Co Ltd (CATL), the official Xinhua news agency said on Thursday.