Hundreds of people marched in London, Berlin and Amsterdam, Netherlands, holding signs emblazoned with the hashtag #BlackLivesMatter and chanting, "No justice, no peace."
They followed similar protests across the United States after police shot dead two black men -- Alton Sterling on Tuesday in Louisiana
and Philando Castile on Wednesday in Minnesota.
The same week, sniper Micah Xavier Johnson killed five police officers
at a Black Lives Matter rally in Dallas.
There have since been hundreds of demonstrations
against Sterling's and Castile's deaths in U.S. cities -- while most have been peaceful, at least 309 people have been arrested in clashes between police and protesters.
How do they compare with the atmosphere in Europe?
Almost 1,000 people took part in rallies in the UK capital over the weekend, many saying they were there to show their support to black families in the United States.
"Every day I wake up another black person is dead -- that's why I'm here today," one protester told CNN.
"People need to know that Black Lives Matter is not a hate group, it's not some radicalized group. We're peacefully marching, we're trying to get our message across."
Traffic came to a standstill as police escorted demonstrators through the city.
One man was charged with being drunk and disorderly at a rally in Brixton, south London.
Some protesters in Berlin were moved to tears Sunday during an emotional reading of the names of black people killed by police in the United States this year.
"When they read their names out loud, the whole crowd repeated it and said, 'Say their names' -- the list was so long though that eventually so many people started crying out in disbelief and horror," said protester Chelsea von Holst.
"It felt like even though I didn't know anyone, we were a strong group of friends who all wanted to protect each other. It was quite remarkable."
Protesters lay down in Potsdamer Platz while the names were read out. There were no arrests during the peaceful demonstration at the public square.
In the Netherlands, protesters wore signs on their backs saying, "Don't shoot -- I'm Trayvon Martin," referring to the 2012 shooting death of 17-year-old African-American Trayvon Martin
by neighborhood watch volunteer George Zimmerman.
Hundreds gathered at Dam Square in Amsterdam city center for the Black Lives Matter rally.
"The atmosphere was peaceful but intense -- emotions all around," said protester Anna Westerveld.