U.N. Secretary-General Ban Ki-moon Monday strongly condemned the "continued, unlawful" acts of armed fighters in Ukraine after reports they are regrouping in eastern provinces, and urged Ukrainian authorities to exercise maximum restraint and protect civilians. According to media reports, armed groups have regrouped in Donetsk and Lugansk, from which more and more residents have fled and others are trapped in zones of heavy fighting. An extended ceasefire that Ukrainian President Petro Poroshenko had put in place June 30 ended, resulting in Ukrainian forces to engage in what Ban called "intensified military activity." Ban's office said in a statement that the U.N. chief also underscored the importance of a "renewed and lasting cease-fire upheld by all parties" and a political solution to the ongoing crisis. "The continuation of a political and diplomatic process towards a definitive cessation of violence and a peaceful resolution of the crisis is critical," the statement said.