Russia launched three Iranian communications satellites into orbit on Sunday, marking the second such joint launch since July, according to Iranian state media.

The satellites—Paya, Kowsar, and Zafar-2—were placed in a 500-kilometer orbit from Russia’s Vostochny launchpad, with Paya being Iran’s heaviest satellite to date at 150 kilograms.

The satellites, with up to 3-meter resolution imaging, will support water management, agriculture, and environmental monitoring, and are expected to operate for up to five years.

The launches reflect strong Russia-Iran ties, strengthened by a “strategic partnership” treaty signed in January, and follow heightened tensions after Israeli and U.S. strikes in June, NPR has reported.

The U.S. has criticized Iran’s satellite program as violating a U.N. Security Council resolution and potentially supporting ballistic missile capabilities.