Mexico's foreign reserves dropped by $59 million last week to $176.47 billion, the Bank of Mexico said in a statement.

Foreign reserves declined by $55 million from Dec. 31, 2013, to Jan. 17, the central bank said Tuesday.

The decline in reserves last week was mainly caused by a change in the value of foreign assets held by the central bank, monetary officials said.

The money supply contracted by 8.12 billion pesos (about $614 million) to 876.36 billion pesos (some $66.24 billion) last week, the Bank of Mexico said.

The money supply has contracted by 41.52 billion pesos (about $3.14 billion) since the start of the year, the central bank said.