US Democratic presidential candidate Bernie Sanders has another chance on Tuesday to block Hillary Clinton's path to the Democratic presidential nomination during the West Virginia state primary election.

Clinton has a lead in the pledged delegates needed to clinch her party's nomination for the general election in November to succeed Democratic President Barack Obama.

Opinion polls show Sanders, a US senator from Vermont, has a slight lead in West Virginia over Clinton, a former secretary of state and US senator from New York state.

Clinton apologized in West Virginia last week after being confronted by angry voters for her remark in March that she would "put a lot of coal miners and coal companies out of business" with her plans to increase renewable energy sources.

Clinton's battle with Sanders, who defied pollsters to win in Indiana state last week, has become a source of rejoicing for presumptive Republican nominee Donald Trump.

Trump, a New York real estate developer, has taunted Clinton in recent days by saying she "can't close the deal" with Sanders, her only rival since February 1.

Sanders has reminded his supporters at crowded rallies that most polls show him beating Trump by a larger margin than does Clinton.

A win in West Virginia would bolster his decision to keep fighting for votes through the Democratic Party’s presidential nominating convention in July.

Sanders, who has been embraced in particular by younger, more left-leaning Democratic voters, has vowed to take his campaign to the nominating convention.

According to the latest NBC News|SurveyMonkey Weekly Election Tracking Poll, Sanders has closed the gap slightly on Clinton nationally following his victory in the Indiana primary last week.

Sanders has 41 percent support this week, and Clinton has 53 percent support among Democrats and Democratic-leaners.

Among Independents who lean toward the Democratic Party, Sanders has a 15-point lead over Clinton. Among those under 30 years old, Sanders has 70 percent support this week compared to 26 percent for Clinton.

Young people have been a key constituency for Sanders throughout the primary season both in the tracking poll and according to NBC News Exit Poll results.