SHANGHAI, May 8 (Reuters) - Mainland Chinese and Hong Kong stocks slipped on Friday, as renewed hostilities broke out between the United States and Iran, threatening a shaky ceasefire, while investors awaited next week's meeting between top leaders of the world's two largest economies.

** At the midday break, the benchmark Shanghai Composite index .SSEC lost 0.43%, while the blue-chip CSI300 Index .CSI300 fell 0.9%.

** In Hong Kong, the benchmark Hang Seng Index .HSI declined 1.09%, while the city's tech shares .HTECH eased 1.08%.

** For the week, both SSEC and CSI300 looked set for their fifth straight weekly rise, with the former set to gain 1.22% and the latter up 1.02% this week.

** The HSI looked set to gain 2.17% for the week.

** The United ​States and Iran exchanged fire on Thursday in the most serious test yet of their month-long ceasefire, but Iran said the situation returned to normal ‌while the U.S. said it did not want to escalate.

** Semiconductor shares led the losses, as investors took profit following recent gains. A sub-index .CSI990001 tracking the sector lost 3.49%.

** Shanghai's tech-focused STAR50 Index .STAR50 dropped 2.9% at the lunch break.

** "China remains a relative bright spot, supported by strong risk appetite and renewed inflows," Wee Khoon Chong, APAC macro strategist at BNY, said in a note.

** "Geopolitics (Middle East) and next week's U.S.–China developments are key near-term catalysts."

** Much of the market attention will shift to U.S. President Donald Trump's visit to China next week and a string of domestic data, including trade on Saturday, inflation on Monday, and credit lending data later next week.

** The White House has invited a scaled-back CEO delegation to accompany Trump to Beijing next week, five sources briefed on preparations said, reflecting divisions in the administration on economic policy toward China and limited expectations for the summit.

** China's export growth likely quickened in April, a Reuters poll showed, as companies rushed to stockpile components from the manufacturing powerhouse amid fears the Iran war could push input costs even higher.