In a telephone conversation on Wednesday, Poroshenko briefed Ban on the situation in Ukraine, including its embattled south-eastern regions.
Ban Ki-moon and Poroshenko also discussed the importance of proper ceasefire monitoring in the east of Ukraine.
The Secretary-General said the U.N. was cooperating with the Organisation for Security and Cooperation in Europe (OSCE) in order to strengthen this mechanism.
The Ukrainian president called for enlarging the monitoring mission.