Proponents have welcomed the consultations as an opportunity to change the Church's power dynamics and give a greater voice to lay Catholics, including women, and marginalized groups.
The appointment of Archbishop Pizzaballa as a cardinal underlines the Vatican's desire to play a more active role in the ongoing diplomatic discussions concerning Jerusalem.
A number of countries, including the United States, face internal political pressure to stop or curtail spending on weapons sent to Ukraine.
Francis spoke out in favor of welcoming migrants, in a long speech that concluded a Church conference on Mediterranean issues.
According to the UNHCR, the UN Refugee Agency, about 178,500 migrants have come to Europe in the year to date via the Mediterranean, while about 2,500 died or went missing on the way.
The cardinal already visited Kyiv and Moscow in June and traveled to Washington the following month.
The bishops' statement said they told the pope that certain statements and gestures of "the Holy See and Your Holiness are painful and difficult for the Ukrainian people."