Brazil's 'worst-ever' weather catastrophe: Over 140 killed, 2 million affected by devastating floods (WATCH)

Strong rains continued to batter waterlogged southern Brazil on Sunday, causing river levels to rise once more. The relentless downpours have already claimed the lives of 145 people and displaced hundreds of thousands from their homes.

Residents of Rio Grande do Sul state were preparing for further hardships as the new rains threatened to exacerbate the situation. Over the past two weeks, incessant rainfall has caused rivers to overflow, engulfing towns and even parts of the regional capital. The deluge has impacted more than two million individuals, with experts attributing the extreme weather to climate change intensified by the El Nino phenomenon.

State authorities confirmed on Sunday that "practically all the major rivers in the state are tending to rise," heightening concerns amid ongoing heavy rains in southern Brazil.

According to the National Center for Monitoring and Warning for Natural Disasters (Cemaden), the likelihood of further flooding remains "very high" in most regions of the state.

Civil defense officials provided an update Sunday evening, revealing that 132 individuals have been reported missing, while an alarming 619,000 people have been displaced from their homes.

Rescue efforts persist as the threat of additional flooding looms, with approximately 130 people still unaccounted for and over 619,000 forced to evacuate.

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In the historic center of Porto Alegre, the state capital, scenes of devastation unfolded as sofas and other belongings floated in muddy waters. Further north, in Sao Leopoldo, a line of partially submerged cars lined the streets where they had been parked. Elsewhere, residents navigated flooded roads using rowboats.

Claudio da Silva, a 36-year-old electrician, described the condition of his neighborhood as "broken," recounting the inundation of his brother-in-law's house, where water had reached halfway up the second floor. He expressed profound sadness at the sight of numerous dead animals amidst the wreckage.

Metallurgist Antonio Vanzan, aged 50, voiced concerns over the critical situation, questioning the consequences if the rainfall persists. He feared a potential rise in river levels and the subsequent re-entry of water into already inundated neighborhoods.

Fresh rains have once again swelled the Guaiba, an estuary bordering the state capital of Porto Alegre in southern Brazil, with levels expected to surpass five meters after reaching their lowest point since May 3 on Saturday.

The Guaiba typically overflows its banks when levels exceed three meters, but recent historic highs of 5.3 meters on May 5 and 6 have exacerbated the situation. Other rivers in the region, already overflowing, continue to rise.

The flooding of the Taquari River has particularly alarmed the small town of Mucum, which is still recovering from a devastating cyclone last September that claimed over 40 lives.

Meanwhile, Pelotas, situated south of Porto Alegre, faces an increasingly dire situation, prompting Mayor Paula Mascarenhas to urge the evacuation of vulnerable areas via Instagram.

Portions of Porto Alegre, housing 1.4 million residents, remain submerged, and heavy rainfall forecasted by the National Institute of Meteorology poses continued threats, with some areas expecting over 100 mm per day.

In the northeast of the state, there is a significant risk of major flooding, river overflow, and substantial landslides.

On Mother's Day, President Luiz Inacio Lula da Silva released a video expressing solidarity with the affected communities, where more than 80,000 individuals are currently residing in shelters. "You are not alone," he assured them.

The federal government has pledged approximately $10 billion for reconstruction efforts in Rio Grande do Sul this week to aid in recovery efforts.