NEW YORK (MarketWatch) — The U.S. dollar hit its highest level against the yen in nearly seven years on Friday, after the Bank of Japan unexpectedly announced new measures to spur Japanese growth.

The dollar USDJPY, +0.01% soared 2.7% to ¥112.33 from ¥109.22 late Thursday. It climbed 3.9% this week and 2.7% this month.

The BOJ on Friday unexpectedly announced additional stimulus measures, underscoring how Prime Minister Shinzo Abe’s economic revival plan has gotten off track since a national sales tax increase in April this year dampened consumer spending.

The BOJ said it would expand its annual asset purchases — its main tool to spur higher inflation — to ¥80 trillion ( or mor than $700 billion) from the previous target range of ¥60 trillion to ¥70 trillion. The central bank aims to achieve the new target mostly by buying more Japanese government bonds, cementing its status as the single largest investor in so-called JGBs.

“In a world where the Japanese Central Bank is accelerating purchases and the U.S. has just completed purchases, that doesn’t bode particularly well for the yen,” said Andrew Wilkinson, chief market analyst at Interactive Brokers.

Wilkinson said the dollar could climb as high as ¥120. J.P. Morgan researchers, meanwhile, revised their year-end target to ¥115.

See: Why Pimco is betting on a stronger dollar

The WSJ Dollar Index BUXX, +0.55% , a measure of the dollar against a basket of major currencies, was up 1.2% at 78.80. The ICE Dollar Index DXY, +0.65% rose to 86.907 from 86.142.