European markets opened trading on Tuesday with a clear decline, giving up the gains they had made at the beginning of the week and the new month, amid anticipation of quarterly results from a number of major companies and expected decisions from central banks.

The pan-European STOXX 600 index fell 1.1% to 565.49 points. The UK's FTSE 100 index declined by 0.7% to 9,631.20 points, Germany's DAX index dropped 1.5% to 23,758.59 points, and France's CAC 40 index fell 1.4% to 7,995.05 points.

European stocks had opened the new week on a positive note, supported by earnings expectations, but a cautious mood returned to investors today, coinciding with the release of third-quarter results for a number of companies, including BP, Philips, Geepart, Associated British Foods and Ferrari.

Earlier today, Saudi Aramco announced that its profits rose by 0.9% in the third quarter thanks to increased production, despite continued pressure on prices.

BP’s results are expected to be closely watched by investors after the company’s stock rose by about 1.2% on Monday, following its announcement of the sale of some of its pipeline assets in the Permian and Eagle Ford regions of the United States to Sixth Street for $1.5 billion.

On the global markets front, Asia-Pacific stock exchanges saw mixed trading overnight, while US stock futures edged down slightly after a strong session on Wall Street on Monday.

The Standard & Poor's 500 and Nasdaq Composite indexes closed higher, supported by continued momentum in artificial intelligence stocks, with Amazon shares jumping to a record high after signing a $38 billion deal with OpenAI, ending the session up 4%.