Former President Mohamed Nasheed has said that the images from Houston, Texas is "saddening," as Storm Harvey continues to ravage America's second largest state.

In a tweet sent out on Tuesday, the former President said that action must be taken now "to strengthen resilience," as extreme weather events become more frequent; tagging US Ambassador to the Maldives, Atul Keshap.

While Hurricane Harvey has been downgraded to a tropical storm, it had caused heavy rains and flooding, which had yet to recede.

So far, nine people are believed to have lost their lives as a result of the conditions, while authorities expected the toll to rise as rescue efforts continue.

According to officials, more than 2,300 calls were made to the Houston Fire Department since midnight Sunday.

Police have rescued more than 1,000 people since Monday morning, bringing the total number rescued to over 3,000 since the storm flooded the city, said Houston Mayor Sylvester Turner.