The Chinese Communist Party's People's Daily used a front page commentary to say the trade war would never bring China down, while talks on Brexit between Britain's opposition Labour Party and the governing Conservatives ended without agreement.
The pan-European STOXX 600 index fell 0.4pc, sliding from Thursday's 10-day closing peak.
The benchmark posted a 1.2pc weekly gain, however, its best performance since early April.
Ben Lofthouse, head of global equity income at Janus Henderson, said investors "have moved from being slightly risk-on to risk off".
"Markets don't deal well with circumstances that are not well rehearsed. For global equities, trade is on people's mind more than Brexit."
Germany's exporter-heavy DAX declined 0.6pc, with BMW shedding 5.2pc as its shares traded ex-dividend.
Milan-traded shares fell 0.2pc, while peers in Paris and London edged 0.2pc and 0.1pc lower, respectively.
The process of the United Kingdom's complex divorce from the European Union was jolted by the opposition Labour Party pronouncing the death of last-ditch talks due to deepening fractures in Prime Minister Theresa May's government.
The news knocked sterling but supported the shares of exporters on the FTSE 100, as a softer pound broadly boosts the value of their overseas earnings.
Real estate stocks shed 1.2pc, with Hammerson PLC down 2.2pc following a price target cut on the stock by RBC.
Banks dropped 1.1pc with the stocks of most lenders on the sector index ending lower.
Italy's Banco BPM fell 3.2pc.
Stocks of auto-makers and their suppliers ended a fourth straight week lower as they dropped 1.1pc on the day. The sector is especially sensitive to worsening US-China trade tensions.
Paris-listed Valeo fell 1.7pc, while Faurecia dropped 1.3pc.
Food delivery companies tumbled after Britain's Deliveroo, which is unlisted, secured funding from Amazon.com Inc.
Just Eat sank 8.2pc, while Amsterdam-listed Takeaway.com and Frankfurt-listed Delivery Hero shed 4.6pc and 2.3pc percent, respectively.
In a bright spot, EasyJet flew 5.3pc higher after the budget carrier said it would meet 2019, expectations despite a weaker trading environment.
The stock boosted the travel and leisure index, which gained 0.8pc.