States must set legally binding global rules on weapon and ammunition sales, aid agency Oxfam said on Tuesday, ahead of a United Nations summit to agree an arms treaty to prevent arms reaching human rights violators.

Citing the example of Syria, which has continued to receive arms shipments even as it is accused of killing more than 9,000 civilians in a crackdown on a popular uprising, Oxfam said it is vital that regulations on weapons sales are strengthened.

There are no internationally agreed rules governing global conventional weapons sales, the United Nations says, and Oxfam says there are more regulations applicable to the banana trade than to weapons.

The aid agency also said the estimated $4.3 billion annual global trade in ammunition is growing at a faster rate than the trade in guns and must be included in any arms treaty.

“The situation in Syria is exactly the sort of situation we hope a robust arms treaty will avoid in future. It’s perhaps not surprising that Syria is among the small group of governments opposing the treaty,” Oxfam head of arms control Anna Macdonald said.

Rights groups have ramped up their calls for stronger arms transfer rules ahead of the U.N. summit in July. Oxfam says 153 countries have voted in support of draft forms of the treaty, but exceptions include Syria and its main arms supplier Russia.

Other objectors include Egypt, Algeria, Iran, Cuba, Venezuela, Pakistan and China.

Russia sold Syria nearly $1 billion worth of arms including missile systems last year, while shipments of Russian small arms have risen since an uprising against Syrian President Bashar al-Assad started in March 2011, government defectors say.

Syria is subject to Western sanctions including an European Union arms embargo, but Oxfam said at least $2.2 billion worth of arms and ammunition had been imported by states under arms embargoes between 2000 and 2010.