WASHINGTON -- China "systematically" impedes access to Tibet with restrictions that have prohibited diplomats, journalists and ordinary citizens from visiting, the United States said in a report Monday.

The State Department documented access problems to the Himalayan region in a report to Congress mandated by the Reciprocal Access to Tibet Act, passed with bipartisan support in December.

The law, which notes that no US region is prohibited, requires the United States by the end of this year to deny visas to Chinese officials in charge of implementing the policy.

"The Chinese government systematically impeded travel to the Tibetan Autonomous Region (TAR) and Tibetan areas outside the TAR for US diplomats and officials, journalists and tourists in 2018," said the report to Congress.

Even visits by US diplomats were "highly restricted," it said.

"Chinese government-designated minders followed US diplomats and officials at all times, prevented them from meeting or speaking with local contacts, interrogated them and restricted their movement in these areas," it said.

Tibet is the only region for which China requires diplomats and journalists to seek special access.

The State Department said that China last year rejected 5 of the 9 US requests to visit Tibet, including one by Ambassador Terry Branstad.

Of the visits that went ahead, 2 were for routine consular matters, one was for the consul general in nearby Chengdu and the other was for security officials to prepare the visit by Branstad that was ultimately denied.

Quoting the Foreign Correspondents' Club of China, the State Department said that only seven international journalists sought permission to visit Tibetan areas last year, compared with dozens in past years, with reporters sensing "the apparent futility of applying."

The report said that China denied access to tourists during times seen as politically sensitive and that Americans of Tibetan ancestry said they were singled out for special screening.

Matteo Mecacci, president of the International Campaign for Tibet, which pushed for the law, welcomed the report as a sign that the United States is "serious" about reciprocal access to Tibet.

"I think it shows that reciprocity with China is a principle that is important not just for trade or economic issues, but also for access for Tibet," said Mecacci, a former Italian member of parliament.

He voiced hope that China, which has protested the law, would address its policies in light of the impending restrictions on visas for officials.

"Our goal is not to bar Chinese officials from coming here. It's to end the isolation of Tibet," he said.