U.S. President Joe Biden's approval rating has fallen to the lowest point in his seven-month presidency, amid the rise in U.S. COVID-19 cases and the chaotic military withdrawal from Afghanistan, according to a new poll by U.S. broadcaster NBC.

The poll, conducted from Aug. 14 to 17 and released on Sunday, found 49 percent of respondents approve of Biden's job performance -- sliding below 50 percent for the first time, while 48 percent disapprove.

An NBC poll in April found 53 percent of Americans approved of Biden's job performance. Other polls last week also found Biden's approval rating slipping, with a CBS survey putting it at 50 percent, Ipsos 46 percent, and YouGov 44 percent.

For his handling of the campaign against COVID-19, the mid-August NBC poll found 53 percent of Americans approve of his performance, a 16-point drop from the April poll.

Only 25 percent of the respondents this month said they approve of Biden's handling of the withdrawal from Afghanistan, which was quickly taken over by the Taliban.

Biden's grade for the economy has also fallen, as 47 percent approve of his handling of the economy, down from 52 percent in April, the poll showed.