Cluster bombs should not be sent to help Ukraine, the Spanish defence minister said on Saturday, a day after the United States announced the weapons would be sent to Kyiv to help with its counter-offensive against Russian forces. Cluster munitions are prohibited by more than 100 countries, including Spain. They typically release large numbers of smaller bomblets that can kill indiscriminately over a wide area. Those that fail to explode pose a danger for decades.

"Spain, based on the firm commitment it has with Ukraine, also has a firm commitment that certain weapons and bombs cannot be delivered under any circumstances," Margarita Robles told reporters during a rally in Madrid ahead of the July 23 national election. "No to cluster bombs and yes to the legitimate defence of Ukraine, which we understand should not be carried out with cluster bombs."

Robles said the decision to send cluster bombs was a decision taken by the U.S. government, not by NATO, of which Spain is a member. There is broad support among Spanish parties for backing Ukraine and providing military aid for the war. Russia, Ukraine and the United States have not signed on to the Convention on Cluster Munitions, which bans production, stockpiling, use and transfer of the weapons.

White House national security adviser Jake Sullivan said Ukraine had provided written assurances that it was going to use them "in a very careful way" to minimise the risk to civilians. Asked why he was providing the cluster munitions now, President Joe Biden told reporters that it was because the effort to defend against Russia had "run out of ammunition".