Two Nigerian nationals under arrest for allegedly overstaying their visas were served further warrants Tuesday on suspicion of trying to smuggle 20 fake $100 bills into the country, Metropolitan Police Department and Tokyo customs officials said.

They were identified as Philip Osaretin Okunrobo, 32, a resident of Adachi Ward, Tokyo, and Abass Kolawole, 31, of Soka, Saitama Prefecture. Both have denied the allegations, according to police.

Investigators said the printing on the notes was blurred, and they were thus easily distinguishable from genuine $100 bills. The suspects will be questioned over who printed the fake bills and for what purpose, they added.

According to police, the 20 bills were hidden inside the pages of magazines whose pages had been glued together. The pair allegedly had the magazines mailed through the international post from Nigeria to a 28-year-old man residing in Soka around last Nov. 13.

The magazines and their contents were discovered by customs officials at the Tokyo International Post Office on Nov. 18 and subsequently confiscated.

The man to whom the magazines were addressed had been away a long time, and investigations showed that the two suspects used to work at a clothing store that the man operated. A search of Okunrobo's home on Nov. 22 turned up a fake $100 note similar to the ones found by customs, police said.

This bill was found in mail that had been posted to a European country but returned, they added.

The suspects had both overstayed their visas and were arrested, one in November and the other in December, for allegedly violating immigration law.