BEIJING (Reuters) - China warned the West not to put its fingers into Tibet as the anniversary on Saturday of riots in Lhasa passed with heavy security to prevent any challenge to Beijing's rule.

Rioting broke out in Lhasa on March 14 last year after days of protests against Chinese rule by Buddhist monks, killing 19 people and sparking waves of protests across Tibetan areas. Exile groups say more than 200 people died in the crackdown.

Twelve months on, a web of troops and police across Tibetan areas deterred any flare ups and by the evening there were no reports of protests.

Matt Whitticase, a London-based spokesman for Free Tibet, a group critical of Chinese rule in the region, said the group's contacts had not called to report any protests on Saturday. But he also said the region had been under a communications shut-down, making it difficult to collect reports.

China's state-controlled media barely mentioned last year's unrest. The main television news on Saturday featured upbeat reports of Tibetans urging stability and praising the government.

Tibet's Communist Party chief, Zhang Qingli, told troops in the region that they faced a complex and grim situation, the official Tibet Daily said on Saturday.

Thoroughly defeat the Dalai clique's plots to try to split the motherland and cause chaos in Tibet, it paraphrased Zhang as saying, though he did not directly mention last year's unrest.

Overseas activists planned to mark the anniversary with a demonstration in New York, but the official Xinhua agency slammed Western critics of China's rule as misguided do-gooders.

They might as well bow their heads, mourn those who died in the Lhasa riots last year, and think twice before putting their fingers into something they are ignorant of again, Xinhua said in an English-language opinion piece that appeared aimed at readers outside China.

Beijing has promised the region will be calm this year and President Hu Jintao called for a Great Wall of stability there.

Tibet and ethnic Tibetan areas of surrounding provinces are under heavy military presence and strictly off limits to foreign journalists and even tourists. Armed police manning road-blocks turned back would-be visitors.

A trickle of isolated protests in recent weeks, including a monk who set himself on fire at the Kirti monastery in Western Sichuan, suggest lingering discontent.

Many Tibetans did not celebrate their New Year in February, in silent protest and mourning for those who died last year.

Lhasa residents reached by phone said the day was like any other, but declined to comment on the security situation.

(Additional reporting by Lucy Hornby, Ben Blanchard and Chris Buckley; Editing by Alison Williams)