Sources in Moscow and Kiev tell the Russian newspaper Kommersant that Russian President Vladimir Putin and Ukrainian President Petro Poroshenko continue to speak on the phone, though both leaders regularly trade harsh accusations in public.

According to Kommersant, the latest conversation between Putin and Poroshenko took place in early April. The two leaders reportedly spent 20 minutes discussing the conflict in eastern Ukraine, where pro-Russian separatists have taken control of areas in Donetsk and Luhansk. Kommersant’s sources say the most recent call took place at Poroshenko’s request.

The two presidents reportedly speak to one another “respectfully and cordially,” sometimes even joking “ironically,” Kommersant says, adding that these phone calls have yet to produce any formal agreements, though Putin and Poroshenko have managed to coordinate some “humanitarian decisions” on prisoner exchange, food supply, pension payments, and water and power in the Donbas, the newspaper says.