Israeli Premier Binyamin Netanyahu is “fully determined” to halt sales by Russia of advanced missiles to Syria when he visits Moscow for talks with President Vladimir Putin, Energy and Water Minister Silvan Shalom said on Sunday.

A reported Russian plan to sell Damascus S-300 missile batteries “worries us at the highest level and the prime minister is fully determined that this contract should not be fulfilled,” Shalom, a member of the security cabinet, told public radio.

“Such a sale to Syria would alter the balance of forces in the region and these weapons could fall into the hands of Hizbullah,” the ally of Syrian President Bashar al-Assad and Iran, Shalom said.

Should Syria obtain the ultra-modern Russian weapons, which can destroy aircraft or guided missiles, “action by countries seeking change in Syria would become much more difficult,” he added, according to the AFP news agency.

Russian and Israeli officials have said the two leaders are to meet shortly, with Russia’s Interfax news agency quoting Putin’s spokesman Dmitry Peskov as saying the visit was being planned for next week.

Israel carried out air strikes near Damascus twice last week, which were aimed at preventing the transfer of sophisticated weapons to the Hizbullah terrorist organization.

US Secretary of State John Kerry has warned that the sale of S300s to Damascus would be “potentially destabilizing” for the region.

Russia however refuses to rule it out however, saying it has to honor existing contracts.

On a visit to Warsaw on Friday, Foreign Minister Sergei Lavrov said Moscow was continuing to fulfill agreements by delivering military hardware to Assad’s regime in defiance of calls for a freeze.

“Russia has sold and signed contracts a long time ago, and is completing supplies of the equipment, which is anti-aircraft systems, according to the already signed contracts,” he told reporters, according to AFP.