Kenyan President Mwai Kibaki has opened an international landmine conference with an appeal for more countries to sign up to the treaty banning them.
Every day there are still dozens of casualties - many of them children
Mr Kibaki told the gathering in Nairobi that the mines were one of the world's most urgent humanitarian problems.
The US, China and Russia are among 40 countries that have not signed the treaty, known as the Ottawa Convention, which came into force five years ago.
The meeting is reviewing progress in eliminating landmines since then.
An estimated 35 million stockpiled landmines have been destroyed, and another four million have been cleared from the ground.
But every year an estimated 20,000 people still become victims of landmine explosions.
'Join the convention'
Mr Kibaki said far more needed to be done.
"It is estimated that there are still close to 200 million mines held by various states," he said. "I appeal to those states that are still not parties to join the convention and to destroy those landmine stockpiles."
At the conference, Ethiopia became the 144th country to sign up to the treaty.
Since 1999, more than 150 countries have agreed to ban the use of landmines targeted at individuals. Mines intended to destroy vehicles fall outside the convention.
Of those yet to sign, the US announced earlier this year that it would make all its landmines detectable and destroy those not timed to self-destruct, but reserved the right to use the weapons to defend its forces.
It is also estimated that 15 countries are still producing anti-personnel mines.
Every day there are still dozens of landmine casualties - almost exclusively civilians, many of them children.
And in countries like Afghanistan, Cambodia and Angola, where people displaced by conflict are returning to their homes, the death and injury toll is very high.
There is also concern in some quarters that donor funding for mine clearance is falling, and that not enough is being done to help rehabilitate mine victims.
Politicians and officials gathering in Nairobi will be urged to redouble their efforts to meet and exceed targets to rid the world of landmines.