(Reuters) -Cisco Systems Inc shares on Thursday touched an 18-month low after the company warned of persisting shortages in components, worrying Wall Street on how exports could suffer due to China's COVID restrictions and the Ukraine crisis.

World stock markets suffered more heavy falls on Thursday after stark warnings from some of the world's biggest retailers about just how hard inflation is biting gave Wall Street its worst day in almost two years.

The S&P 500 and the Dow extended losses on Thursday as Cisco Systems slumped after it gave a dismal outlook, while investors fretted over the impact of surging inflation on economic growth and corporate earnings.

Swedish electric-vehicle maker Polestar cut its 2022 delivery forecast by 15,000 units to 50,000 vehicles on Thursday, hit by COVID-19 lockdowns in China.

(Reuters) -Kohl's Corp cut its full-year earnings forecast on Thursday, joining some of the largest U.S. retailers in warning that red-hot inflation is starting to erode profit margins and consumer spending power.

Wall Street's main indexes opened lower on Thursday after the S&P 500's biggest rout this year in the previous session, as investors fretted over the impact of surging inflation on the economy and corporate earnings.