<p> A letter bomb went off on Thursday at an office of ING Bank in Amsterdam, causing a "small explosion" in which no one was hurt, a spokeswoman for the bank said.</p>.<p>A series of letter bombs have been sent in the country this week, including one disarmed near Utrecht earlier on Thursday.</p>.<p>Police said an ambulance was sent to the ING building as a precaution after one person had inhaled smoke there.</p>
<p> A letter bomb went off on Thursday at an office of ING Bank in Amsterdam, causing a "small explosion" in which no one was hurt, a spokeswoman for the bank said.</p>.<p>A series of letter bombs have been sent in the country this week, including one disarmed near Utrecht earlier on Thursday.</p>.<p>Police said an ambulance was sent to the ING building as a precaution after one person had inhaled smoke there.</p>