Chinese stocks closed slightly lower on Friday but finished the first half of the year strong, with the two major indexes posting huge gains and outperforming those in the US.

The Shanghai Composite Index gained 19.45 percent in the first half of 2019, despite closing 0.6 percent lower on Friday, while the smaller Shenzhen Component Index rose 26.78 percent during the period, after closing 0.66 percent down.

The gains posted by the two Chinese indexes were significantly higher than that of major indexes on Wall Street in about the same period. As of market close on Thursday US time, the Dow Jones Industrial Average gained 13.62 percent in the first half of 2019, and the S&P 500 rose by 16.53 percent. That could mean some upsetting news for US President Donald Trump as he heads into a high-stake meeting with President Xi Jinping to take another attempt to ease tensions and resume trade talks.

Trump had repeatedly boasted gains on Wall Street as one of his major achievements as US president. As recent as Tuesday, Trump tweeted that "stock market is heading for one of the best months (June) in the history of our country. Thank you Mr. President!"

While the S&P 500 and the Dow were on track for the best performances in decades, many analysts in the US have pointed warning signs ahead, including the trade war, and expected challenges for the US economy.

In China, market analysts are more upbeat about the second half of the year, as policymakers continue to carry out massive stimulus measures, including big cuts to fees and taxes for companies.