Many thousands of people have taken to the streets across Europe as part of traditional May Day protests.
Russians called for a "social state" during marches in Moscow
Some 25,000 Russian trade unionists - and several thousand Communists - marched in Moscow for social welfare.
In Belarus, more than 1,000 opposition supporters held a show of defiance after the jailing of their leaders on Thursday over another protest.
While in Turkey, police clashed with at least 20 protesters who held a rally in an unauthorised area of Istanbul.
Tens of thousands of Germans meanwhile called on the government not to dilute peoples' rights as it tackles reforms.
"The government should not put in place anti-social policies," said Michael Sommer, president of the German Federation of Trade Unions (DGB), at a rally in Wolfsburg, home to the headquarters of car manufacturer Volkswagen.
Car workers for the Peugeot factory in the UK were attending the May Day rally in London to protest at plans to cut 2,300 jobs.
Elsewhere in the world:
- Union and civic leaders in Zimbabwe protest over worsening hardship under President Robert Mugabe, and ask police not to beat them
- Thousands of Iranian workers demonstrate in Tehran over the growing use of short-term employment contracts
- Police in the Philippines and Indonesia are put on high alert amid fears the rallies could turn into anti-government protests
- Cambodia briefly arrests labour head Chea Mony as hundreds attempt to defy a ban on marches in the capital Phnom Penh
Russian police spokesman, Viktor Biryukov, said trade unionists marched peacefully through central Moscow calling for a "social state," according to Itar-Tass news agency.
A smaller group of Communist Party supporters marched from Lenin monument on October Square to their usual rally spot at the Karl Marx statue. They chanted "Putin resign!", "Our Homeland is the USSR".
The May Day march in the Belarus capital, Minsk - sanctioned by the city's officials - was nominally used to call for an end to short-term labour contracts.
But the main focus of the protest was to call for the release of opposition leader Alexander Milinkevich and other activists who were jailed for up to 15 days last week.
"Freedom for Milinkevich!" marchers shouted as they passed along the approved route, the AFP news agency reported.
"Not all our friends are here today. Many are behind bars," Alexander Dobrovolsky of the United Civic Party told protesters. "We need solidarity to keep us together every day."
In Istanbul, Turkish police arrested at least 20 left-wing protesters who had gathered in the city's Taksim Square without a necessary permit, according to reports.
Television footage showed the protesters resisting arrest and fighting with police officers who tried to disperse them using tear gas and pepper spray.
Meanwhile, in the city's Kadikoy district, thousands gathered for an approved rally, organised by trade unions and civic organisations. A large rally was also being held in the capital Ankara.