World leaders are devoting their attention to the global economy and prospects for reviving growth on the second day of discussions of the Group of Eight summit in France.
Authorities said they had prepared for the protests
Later, they will debate political issues including President George W Bush's campaign against global terrorism and the spread of weapons of mass destruction.
A summit statement is expected to warn that these two issues pose the key threat to international security - however not all G8 leaders agree on how to tackle them.
The US and French leaders are also having a brief meeting at the talks - their first since the war in Iraq.
Monday's meetings follow overnight clashes in cities near the summit venue - the spa town of Evian, where a security cordon remains in place to prevent protesters getting close to politicians and delegates.
Some of the most serious disturbances took place over the border in Switzerland, with rioting continuing late into the night in the city of Geneva.
The Swiss authorities spent more than nine hours battling anti-globalisation demonstrators as they rampaged through the city centre.
Issues at summit
Weapons of mass destruction
Middle East peace process
Helping developing countries
Police responded with teargas, water cannon and stun grenades after being pelted with stones and petrol bombs.
When they were unable to contain the violence, German police reinforcements were drafted in to help disperse the rioters and take into custody the ringleaders.
Shop windows were smashed and stores looted, while city streets were filled with broken glass and choking fumes from tear gas canisters.
In Lausanne, demonstrators wearing black face masks blocked roads with burning barricades and attacked the hotel area where some summit delegates were staying.
The main complaint of the protesters is that the summit will achieve little in terms of addressing the needs of the world's poor.
The BBC's Emma Jane Kirby in Geneva says that just a few hundred troublemakers caused millions of dollars of damage to homes and businesses, and the people of Geneva will want to know how that was allowed to happen.
At the summit, the diplomatic rift caused by the US-led war in Iraq is expected to overshadow proceedings.
The BBC's diplomatic correspondent Barnaby Mason says UK officials expect a statement to come out of the summit identifying terrorism and the spread of weapons of mass destruction (WMD) as the pre-eminent threat to international security.
Among the measures apparently being considered are steps to prevent radioactive materials falling into the hands of terrorists, and the interception of ships and aircraft suspected of carrying WMD.
This last proposal was announced by President Bush in Poland on Saturday.
However, the French are asking questions about what legal basis such action would have and who would carry it out, our correspondent adds.
White House officials say Mr Bush is anxious to move beyond the divisions over Iraq.
But the BBC's Rob Watson, who is travelling with the US president, says the Bush administration believes it is now up to France and others to make the next move.
The first day of the summit was taken up with discussions between the G8 and leaders of a dozen other big countries from the emerging and developing world.
The meeting of the G8 countries - the US, Japan, Germany, UK, France, Italy, Canada and Russia - ends on Tuesday.