Image caption Tiger numbers have plummeted by 40% in the last decade alone

Governments of 13 countries where tigers still live have endorsed a plan to save the big cats from extinction.

Delegates at a summit in St Petersburg, Russia, agreed to double tiger numbers by 2022.

The countries will focus on protecting tiger habitats, addressing poaching, illegal trade and providing the financial resources for the plan.

In the last 100 years, tiger numbers have dropped from about 100,000 to less than 3,500 tigers in the wild today.

There has been a 40% decline in numbers in a decade, and some populations are expected to disappear within the next 20 years.

The United Nations Environment Programme (Unep) says that the St Petersburg Declaration will strengthen international collaboration to protect the majestic Asian wild cat.

There was clearly a loud roar from St Petersburg this week on behalf of the last remaining tigers on our planet John Robinson, WCS

Elizabeth Maruma Mrema, executive-secretary of Unep's Convention on Migratory Species (CMS) Secretariat, commented: "Safeguarding international migration corridors and trans-border habitats will be crucial for global efforts to save the tiger."

The declaration sets in motion a strategic plan for tiger recovery; the countries are putting together a roadmap for post-summit action.

They are also discussing the institutional structure which will be set up to implement the aims and objectives of the declaration and its recovery programme.

"There was clearly a loud roar from St Petersburg this week on behalf of the last remaining tigers on our planet," commented John Robinson, chief conservation officer with the Wildlife Conservation Society (WCS).

"World leaders rarely find agreements at conferences and summits but the beloved tiger has proven to be a uniting force. And as we save the tiger, we have new hopes to save the world's biodiversity."

Titanic contributions

WCS was one of several groups pledging new money to assist conservation efforts, in this case $50m over 10 years.

The World Bank, whose president Robert Zoellick takes a strong personal interest in the tiger, put in a similar amount, and aims to leverage further funding from governments and the corporate sector.

Hollywood actor Leonardo DiCaprio donated $1m to the effort.

Mr DiCaprio arrived in St Petersburg on Tuesday after two problems with his flights.

One plane was forced into an emergency landing after losing an engine, the other had to make an unscheduled stop after encountering strong headwinds.

Mr Putin described the actor as a "real man" - or "muzhik" - for his persistence in getting to the summit.