European stocks lost value on average at the end of the week, as key leaders congregated for a major event in Argentina.

By the close the pan-European Stoxx 600 was provisionally 0.25 percent lower with the different sectors struggling to make clear gains.

The European index shed 0.92 percent for the week.

Autos and basic resources fell the most as investors focused on the upcoming trade talks at the G-20 summit, in Buenos Aires on Friday. Investors are paying special attention to a meeting between President Donald Trump and China's President Xi Jinping.

The FTSE 100 in London closed down by 0.97 percent provisionally, dragged lower by the high number of mining stocks that lost value over the session.

Ahead of the summit, Trump delivered mixed messages concerning a trade relationship with China; telling reporters on Thursday that the U.S. was "very close to doing something" with China, but added that he wasn't sure whether he wanted to go through with it. Tariffs and trade have been rattling markets in recent months as a tit-for-tat war of words goes on between the two countries.

European investors were also following and reacting to news out of Italy. Prime Minister Giuseppe Conte told an Italian newspaper that he is working on a proposal to reduce the planned deficit target for 2019. The idea is to bridge differences with the European Commission and potentially avert extra monitoring from officials in Brussels. The main Italian stock index was slightly lower in early deals.

Shares of Deutsche Bank traded below the flatline once again, slipping 3.11 percent. The stock remains under pressure as police raids at its offices continue. On Thursday, German police raided Deutsche Bank's headquarters in Frankfurt during an investigation of alleged money laundering.

Another subject expected to cause a stir at the G-20 summit is that of Brexit with continuing as concerns over what the U.K.'s future relationship with the EU will look. Ahead of the summit, U.K. Prime Minister Theresa May told reporters that she was concentrating on winning over lawmakers this December, when the parliamentary vote takes place, rather than dwelling on an alternative Brexit deal — or no deal; Reuters reported.