The United Nations chief has condemned a cut in water supplies in the northern Syrian city of Aleppo that he says has deprived at least 2.5 million people of access to potable water.

UN  Secretary-General Ban Ki-moon said that preventing people access to safe water denies them a "fundamental right." He said in a statement from his office released late Friday that denying civilians essential supplies is a breach of international and humanitarian law.

The director of the Syrian Observatory for Human Rights activist group, Rami Abdurrahman, says that rebels from the al-Qaida-linked Nusra Front cut water supplies in the city nearly two weeks ago.

Abdurrahman said Saturday that the group has tried to resume pumping water, but that supplies are erratic and remain largely cut.