WASHINGTON, July 16 (Reuters) - Psiphon Inc"s freely available internet censorship circumvention tool has about helped nearly 1.4 million Cubans this week gain access to websites, the company said on Friday, after Cuba"s government curbed access to popular social media and messaging platforms. The Toronto-based company"s Psiphon Network receives U.S. government financial support and also helped people in other countries including Iran and China overcome governmental restrictions on internet access. Thousands of Cubans joined nationwide protests over shortages of basic goods, limits on civil liberties and the government"s handling of a surge in COVID-19 infections on Sunday, the most significant unrest in decades in the communist-run country. Psiphon said 1.389 million users accessed the open web from Cuba through its network on Thursday, as well as 1.238 million as noon EDT (1600 GMT) on Friday. "Internet is ON; circumvention tools ARE working," Psiphon said in a statement. Psiphon said the roughly 1.4 million represents about 20% of Cuban internet users. Its open source circumvention tool can be downloaded from app stores like Google Play or Apple to "maximize your chances of bypassing censorship," according to the company. Canadian university researchers developed the software in 2007 to let users evade governmental internet firewalls. Cuba"s government has restricted access to platforms including Facebook and WhatsApp amid the protests, according to global internet monitoring firm NetBlocks. "We must stand with those opposing authoritarian regimes," said U.S. Senator Marsha Blackburn, a congressional supporter of U.S. funding for the network. President Joe Biden said on Thursday the White House is reviewing whether the U.S. government can help Cubans regain internet access. White House spokeswoman Jen Psaki sidestepped questions on Friday about the effort or whether Biden"s administration has reached out to U.S. tech firms.