Police officers tipped off by an anonymous informer forced their way into a Johannesburg apartment where they found 10 rhinoceros horns and an elephant tusk and arrested a Vietnamese man, a police spokesman said Wednesday.

Spokesman Vish Naidoo said the man will appear Friday in court on charges that include illegal possession of rhino horn. The man had refused to let police in when they arrived at the apartment late Tuesday, so they forced open his door, Naidoo said, adding more arrests in the case were possible.

Rhino poaching in South Africa, home to most of the world's rhinos, and across Africa has reached crisis levels. Major markets for the horn are China and Vietnam, where some believe it has medicinal qualities.

Last month, South Africa tightened hunting rules to try to combat illegal horn trading. South African officials take into consideration whether the countries in which foreign applicants live have sufficient laws against illegal rhino horn trading. Vietnam is seen as having lax laws on importing horns.

Police on Tuesday also found several travel documents from different Asian countries and 5 million rand (about $625,000) in cash in the apartment, Naidoo said.

So far this year, more than 200 rhinos have been poached in South Africa, nearly half the record 448 poached all last year. But arrests are also increasing, with 165 so far this year compared to 232 for all last year.

Naidoo said public awareness of the poaching problem and cooperation with authorities is increasing.