(Reuters) - Europe's top human rights court ruled on Tuesday that the Swiss government had violated the human rights of its citizens by failing to do enough to combat climate change.

The European Court of Human Rights' decision on the case brought by more than 2,000 elderly Swiss women set a precedent that will resonate across Europe and beyond for how courts deal with a growing trend of climate litigation.

But in a sign of the complexities of climate litigation, the court rejected two similar climate-related cases, one brought by a group of six Portuguese young people against 32 European governments and another by a former mayor of a low-lying French coastal town.

The Swiss women, known as KlimaSeniorinnen, argued their government's climate inaction put them at risk of dying during heatwaves.

In her ruling, Court President Siofra O'Leary said the Swiss government had failed to meet targets for cutting greenhouse gas emissions and that there had been gaps in its domestic regulatory framework.

"It is clear that future generations are likely to bear an increasingly severe burden of the consequences of present failures and omissions to combat climate change," O'Leary said.

One of KlimaSeniorinnen leaders, Rosmarie Wydler-Wälti said she was struggling to grasp the full extent of the decision.

"We keep asking our lawyers, 'Is that right?'. And they tell us 'it's the most you could have had. The biggest victory possible'."

A spokesperson for the Swiss Energy Ministry reacted to the ruling by saying: "We're on a good path. We're doing a lot."

The cases before the 17-judge panel in Strasbourg, France, are among the increasing number of climate lawsuits brought by communities against governments that hinge on human rights law.

The European Commission said it took note of the ruling.

"Regardless of the legal arguments, what these cases do is they remind us of the high importance and urgency which our citizens attach to climate action." a Commission spokesman said.

Avaaz, a global advocacy organization, said the court's Swiss ruling had opened a new chapter in climate litigation.

"(It) sets a crucial legally binding precedent serving as a blueprint for how to successfully sue your own government over climate failures," said Ruth Delbaere, legal campaigns director at Avaaz.

The verdicts, which cannot be appealed, could compel the Swiss federal government to take greater action on reducing emissions, including revising its 2030 emissions reductions targets to get in line with the Paris Agreement goal of limiting warming to 1.5 degrees Celsius (2.7 Fahrenheit).

In the case brought by the Portuguese youngsters, the court ruled that while a state's greenhouse gas emissions may have an adverse impact on people living outside its borders, it did not justify prosecuting a case across multiple jurisdictions. It also noted that the young people had not exhausted legal avenues within Portugal's national courts before coming to the European Court of Human Rights.

"I really hoped that we would win against all the countries so obviously," Sofia Oliveira, one of the Portuguese teens, said in a statement.

"But the most important thing is that the Court has said in the Swiss women’s case that governments must cut their emissions more to protect human rights. So, their win is a win for us too and a win for everyone."