SYDNEY, May 18 (Reuters) - Tokyo stocks edged higher on Monday as signs of a slowdown in coronavirus infections raised optimism that Japan would soon ease restrictions in additional prefectures, although escalating Sino-U.S. trade tensions kept investors wary.

The benchmark Nikkei average rose 0.7% to 20,177.79 by the midday break, erasing early losses.

The daily number of new coronavirus cases reported in Tokyo dropped to five on Sunday, the lowest since the capital was placed under a state of emergency on April 7.

Japan lifted a state of emergency in large parts of the country on Thursday but said it would remain in place in Tokyo until the novel coronavirus was contained.

Increasing tensions between the United States and China, the world's two largest economies, sent shares of chipmaking-related companies and electric component makers reeling.

The Trump administration on Friday moved to block global chip supplies to blacklisted telecoms equipment giant Huawei Technologies, spurring fears of Chinese retaliation and hammering makers of chipmaking equipment on Wall Street.

Tokyo-listed chipmaking-related stocks also took hit after the Philadelphia semiconductor index lost 2.2% on Friday.

Screen Holdings Co Ltd tumbled 12.5%, while Tokyo Electron Ltd and Advantest Corp slid 2.7% and 2.6%, respectively.

The broader Topix added 0.6% to end at 1,460.06 by the recess, with three-fifths of the 33 sector sub-indexes on the Tokyo exchange trading higher.

Mining, fish and forest and oil and coal products were among the top-performing sub-indexes on the main bourse.

Oil and gas companies Inpex Corp and Japan Petroleum Exploration Co Ltd jumped 3.8% and 7.5% respectively, as U.S. crude prices climbed 7% on Friday to their highest since March on strengthening fuel demand.

Elsewhere, Sumitomo Mitsui Financial Group (SMBC) gained 4.9% as the megabank's annual net profit overtook that of rivals Mitsubishi UFJ Financial Group (MUFG) and Mizuho Financial Group for the first time.

Meanwhile, data showed Japan's economy slipped into recession for the first time in 4-1/2 years, putting the nation on course for its deepest postwar slump, but had limited impact on the market. (Reporting by Tomo Uetake; Editing by Subhranshu Sahu)