Voters are starting to cast their ballots in the United States' midterm elections as polls opened at 6 a.m. Eastern Time (1100 GMT) on Tuesday in several eastern US states, including Maine, New York and Virginia. 

Amid persistently high inflation and rising living costs, this year's midterm elections are shaping up to be a major test for the Trump administration in its second term.

Republicans and Democrats are competing for all 435 seats in the House of Representatives and 35 of the 100 seats in the Senate. Voters will also elect governors in 36 states, along with state legislators and other local officials in various states.

Democrats need a net gain of just three seats to take control of the House of Representatives. The latest projections from the Cook Political Report, a nonpartisan US newsletter, suggest Democrats could pick up between 12 to 25 seats in the House. Many observers expect the chamber to flip to Democratic control.

The Senate race, however, remains more competitive and uncertain, with seven states - Maine, Texas, Michigan, Iowa, Ohio, Kansas and Alaska - emerging as particularly competitive battlegrounds. Democrats need a net gain of four seats to secure a 51-seat majority in the Senate.

In recent days, Xinhua reporters visited Maine, Texas, North Carolina and Georgia, among other states, and found that inflation and the rising cost of living were among American voters' top concerns this year.

Many voters blamed the Trump administration's policies for rising gas and food prices, expressing particular frustration over its war with Iran and its sweeping tariffs. Other issues drawing widespread attention included immigration policy, healthcare and corruption.

A survey released in mid-October by the AP-NORC Center for Public Affairs Research, a joint initiative of The Associated Press and the University of Chicago, found that 85% of voters cited the economy and 84% cited the cost of living as among the most important issues in this year's midterm elections. The poll also found that 74% of respondents disapproved of President Donald Trump's handling of the economy, while 79% disapproved of his handling of the cost of living.

Over the past several weeks, more than 50 million US voters have already cast their ballots in early voting. According to The New York Times, turnout in several key Senate battleground states has surpassed levels recorded at the same point in the previous midterm election cycle. The report, however, noted that roughly half of all votes nationwide were cast on Election Day in recent elections.

Polls in eastern states generally close at 7 p.m. Eastern Time on Tuesday, while those in central and western states remain open later. By 9 p.m. Eastern Time, polls will have closed in more than 80% of states nationwide. Alaska, in the far northwest, will be the last state to close its polls, at 1 a.m. Eastern Time on November 4.

US media outlets expect control of the House to become clear relatively early, given the potentially wider margins in many races. The Senate, however, could take much longer to call, with seven states facing particularly tight contests.

National Public Radio, an independent, nonprofit US media organization, estimates that vote counting, which is set to begin Tuesday night, could take days or even weeks to complete.