U.N. human rights chief Michelle Bachelet said Monday strikes on civilians in the ongoing Nagorno-Karabakh conflict could constitute war crimes, and called again for a halt to attacks on towns, schools and hospitals. This comes after Armenia’s leader asked Russia for military assistance, after Azerbaijan’s army pressed deeper into the disputed region of Nagorno-Karabakh over the weekend. The conflict has entered its sixth week, with three failed ceasefire agreements. Armenia has also called for an investigation into the presence of “foreign mercenaries” after Armenian forces said they captured two fighters from Syria. Azerbaijan’s president said Monday he is ready to end fighting if Armenia pledges to pull out of Nagorno-Karabakh. A day earlier, he warned his army is prepared to fight Armenia “to the end.”