European stocks close 4.5% lower as global markets seesaw on tariff uncertainty

European stocks sank for a fourth straight session on Monday, amid a global equity market rout that kicked off last week following the latest announcements of U.S. President Donald Trump's tariffs regime.

The pan-European Stoxx 600 index fell up to 6% earlier in the session, but slightly pared losses to close 4.54% lower. France's CAC 40 tumbled 4.8% as Germany's DAX shed 4.26% and the U.K.'s FTSE 100 lost 4.4%.

U.S. stocks, which tanked toward the end of last week as the "Magnificent Seven" mega-cap tech stocks lost more than $1 trillion in a single day, were also sharply lower on Monday.

Global equity markets were rocked during the afternoon Europe session, briefly spiking into the green following a media report and social media speculation about a potential tariff pause. White House Press Secretary Karoline Leavitt told CNBC's Eamon Javers on Monday that any talk of a 90-day pause was "fake news."

Further uncertainty was delivered just before the European close, as Trump threatened to hike tariffs on China by another 50% unless it scraps retaliatory duties.