ISLAMABAD, Pakistan  With Pakistanis bracing for more rain and floods, President Asif Ali Zardari struggled Friday to confront a barrage of criticism over his recent visit to Europe, undertaken while rivers gorged by monsoon rains ravaged large portions of the country  a trip that critics have derided as “insensitive” and a “joy ride.”

The flooding, which began in late July, has killed an estimated 1,600 people and affected 14 million, according to relief agencies. Aid agencies and the United Nations warned on Friday that the disaster was still mounting, with devastating outbreaks of water-borne disease an additional likelihood.

“We want to warn everyone that the crisis facing Pakistan is enormous,” said Mengesha Kebede, a representative of the United Nations refugee agency. “There continues to be massive destruction as the bloated rivers flow inexorably southwards across the plains.”