In a statement, the World Bank said that as a development partner of Bangladesh, it was "deeply concerned about the adverse effects on services to the poor, should such attacks escalate".
Six employees of Bangladesh Rural Advancement Committee were injured when unidentified people hurled bombs at its office in western Naogaon district on Tuesday night. In a similar incident a day later, two employees of the 'Grameen Bank' of Professor Mohammad Yunus were injured in northern Sirajganj district.
"It is important that development agencies like BRAC and Grameen Bank be able to continue their work unhindered by fear or violence," the Bank said.
Meanwhile, officials at the NGOs tightened security at their offices following the attacks, media reports said.
Terming the attacks as a "bad omen" for Bangladesh, Yunus told the Daily Star newspaper that "it is not an isolated local or religious incident, but a political and planned attack".
"Religious fanaticism was a factor behind the attacks on BRAC offices", the newspaper quoted executive director of BRAC, Abdul Muyeed Chowdhury as saying.
State Minister for Home Affairs Lufuzzaman Baber told Parliament yesterday that steps to check the violence were underway.