Two U.S. senators urged President Barack Obama's administration "to step up its fight against China's hoarding of critical rare earth elements" by blocking funding for Chinese mining projects.

Democratic senators Charles Schumer and Debbie Stabenow said they urged Treasury Secretary Timothy Geithner in a letter to use U.S. influence in the World Bank and other multilateral lending institutions to block funding for any Chinese mining project in China or abroad.

They also asked U.S. Interior Secretary Ken Salazar to block any Chinese mining project in the United States "until the Chinese end their anti-competitive practices with regard to REEs," the senators said in a news release.

Schumer and Stabenow scheduled a news conference for later on Tuesday to discuss their concerns.

China produces 97 percent of global rare earth supplies, giving it a stranglehold on a range of vital elements used in defense technologies, wind turbines and batteries for electric vehicles, computers and mobile phones.

Beijing cut export quotas by 40 percent last year, alarming buyers and trading partners. China has again cut export quotas for the first half of 2011 by 35 percent from the first half of last year.

The Obama administration has been considering for at least six months whether to challenge China's rare export restrictions as a violation of commitments Beijing made when it joined the World Trade Organization in 2001. (Reuters)