BEIJING, July 7 (Reuters) - Heavy rain battered China's north-eastern rust belt on Thursday (Jul 7), triggering floods that trapped buses, swamped roads and disrupted commuters in cities, with more storms forecast for coming days.

In Shenyang, capital of Liaoning province, its 7.6 million residents were caught off-guard by the unexpectedly heavy rain even though several red alerts, the highest in a four-tier storm warning system, were issued on Wednesday.

Residents woke up to public messages on their mobile phones telling them to delay heading to work and call off any non-essential activities because of "extreme weather".

Traffic police data showed 52 waterlogged sections of roads, 30 of which were closed.

Five students and a driver were marooned in a school bus in one inundated area and had to be saved by rescuers in rubber boats, state television reported.

From the province of Hebei in the north to Anhui in the east, many motorists were trapped in their cars as engines stalled on waterlogged roads, state television footage showed this week.

In the past month, China has grappled with extreme weather from heatwaves to historic floods, with meteorologists blaming climate change and also the first typhoon of the season, Chaba.

Alerts for flood risks were also issued in Jilin province, north of Liaoning.

In Yanji, a Jilin city on the border with North Korea, a man was hailed for his bravery on social media after he dived into a raging river to rescue his wife despite not knowing how to swim, footage from state-run Xinhua news agency showed.

The two sustained some scrapes but suffered no severe injuries.

"I swear in my next life, I'll still marry him," the wife said in the footage, smiling.

Over the next 12 hours, flood-swollen rivers were expected to inundate farmland and urban areas in the cities of Changchun and Siping.

Liaoning and Jilin are expected to see more heavy downpours in the next two days before the rains start to dissipate.