Cluster munitions are often crude and unreliable weapons.
Launched from the air or the ground, they can release hundreds of smaller sub-munitions to attack a target.
Globally, since the 1960s, they have killed more than 21,000 people.
But a report by the leading international monitor of the use of such weapons, the Cluster Munition Coalition, says almost a thousand casualties were directly related to them just in 2016.
Those casualties, mostly in the civil wars in Syria and Yemen, were double the number in the previous year.
And the coalition’s landmine and cluster-munition monitor, Loren Persi, says the weapons can cause harm for decades after they are first deployed.
“The majority of all casualties from unexploded remnants of war were from cluster munitions, and many of them were children, and it is definitely an indication that Laos, which is a ‘states’ party, and many of the countries that are affected are still affected by these munitions many years later.”
The rising figures come despite an increasing number of countries ratifying an international treaty prohibiting their use.
Officials say it is becoming increasingly difficult to monitor cluster munitions, with some speculating the number of attacks was actually far higher than the 200 recorded.
The advocacy director from Human Rights Watch’s Arms Division, Mary Wareham, singles out the ongoing conflict in Syria.
“The vast majority of that use has been by Syrian government forces. And, last December, the Russian foreign minister sent us a letter with a three-page policy position paper about cluster munitions in Syria. He did not explicitly deny or confirm Russia’s involvement in the use, but it denied that cluster munitions were being used indiscriminately in Syria. We disagree.”
The latest report was released at United Nations headquarters in Geneva.
The United Nations has also raised concerns over a sudden rise in air strikes hitting the Syrian city of Raqqa last month.
A United States-led coalition, seeking to oust IS from the city, conducted more than a thousand strikes on Raqqa, up from 645 in July.
And Russia’s air force, backing Syrian government troops along with Iran, reported carrying out more than 2,500 air strikes across Syria in the first three weeks of August alone.
The UN human rights office says forces may be violating international law and endangering civilians.
Spokeswoman Ravina Shamdasani has urged both sides to remember what they are fighting for.
“If you’re going to pummel civilians, if you’re going to cause massive loss of civilian life and infrastructure, then what is the point? The point should be to liberate these civilians from ISIL’s murderous regime, not to pummel them so that, in the end, you have a Pyrrhic victory.”