( CNN ) -- Bangladesh police have detained or arrested more than 18,000 people in the last 11 days in a crackdown on crime they say is aimed at improving security ahead of December elections . People arrested by Bangladesh police in their latest round-up arrive at a jail in Dhaka . Human rights groups decry the actions as politically motivated . The round-ups began May 28 , days after the two main political parties said they would not cooperate with the military-backed caretaker government on organizing the elections . Police told CNN that by Saturday 16,916 arrests had been made , while local media reported another 1,548 were arrested Sunday . The Awami League and the Bangladesh Nationalist Party ( BNP ) said hundreds of their party members had been taken into custody . `` The timing and targets of the arrests are a dead giveaway they are politically motivated , '' Brad Adams of the New York-based Human Rights Watch said in a statement . `` It 's obvious that they are paying the price for the political parties ' refusal to accept the government 's conditions to participate in the elections . '' The government rejects the allegations . The detentions , it said , are part of a planned sweep to rid the country of criminals . `` Our IGP [ Inspector General of Police , or chief of police ] categorically said this special drive was being conducted to create a congenial atmosphere before the general election , '' said Kamrul Ahsan , a spokesman for Bangladesh Police . `` It is not politically motivated , '' he said . `` The intention is not to harass anybody politically . '' The crackdown began after the Awami League and the BNP said they would not cooperate with the government to develop a roadmap toward democracy unless it first releases the parties ' leaders . The two women who head the parties -- Sheikh Hasina of the Awami League and Khaleda Zia of the BNP -- are in police custody on corruption-related charges . Hasina is charged with bribe-taking . Zia is being held on charges of graft for improperly awarding a multi-million dollar government contract . The current political crisis in the Muslim-majority South Asian country of 150 million can be traced , in large part , to the lingering animosity between the two women , political observers say . Their rivalry runs so deep that the women are known in the country as the `` Battling Begums . '' Begum is an honorific given to women of rank in the country . Since the country 's independence in 1972 , the Awami League or the BNP has ruled Bangladesh for all but eight years . Both women have served as prime minister at one point or another . After its last stint in power ended in 2006 , the BNP handed over rule to a caretaker government to conduct elections , as mandated by the country 's constitution . But the Awami League refused to recognize the neutrality of the interim government . Hasina accused Zia of stocking it with BNP backers . Supporters and party members took to the streets in months of deadly clashes . To stem the tide of violence , a military-backed government took control in January 2007 and imposed an indefinite state of emergency . It also postponed elections until it said it could clean up the country 's graft-ridden politics . The caretaker government adopted the Emergency Powers Rules . The rules allowed authorities to arrest people without a warrant as long as there was reasonable suspicion that he or she was connected to a crime , Human Rights Watch said . A wave of detentions followed . By some estimates more than 90,000 people were detained before some were released and others charged with crimes . Among those arrested were more than 150 top politicians , including Hasina and Zia -- leading to the current political stalemate . The government wants to hold elections in the third week of December , and said the crusade on crime is part of its plan to ensure trouble-free balloting . The political parties allege the arrests are intended to pave the way for the election of pro-government candidates . They want their leaders set free before they sit down and talk with the government about a roadmap toward a successful election . They also threatened to organize mass movements to secure their leaders ' release . `` It 's kind of an impasse , '' said Taleya Rehman , founder and executive director of the Bangladesh-based non-profit Democracy Watch . `` The government is conducting political dialogue with small parties . But they are of no significance . They need the two major parties . '' On Monday , the government announced it was releasing Hasina from custody on medical grounds so she can go abroad for treatment . A similar release for Zia was also expected . Party members say the government 's move is a ploy to sideline the pair from the elections by sending them out of the country . Hasina has a damaged ear resulting from a bombing attack that targeted her four years ago . Zia is believed to have arthritis . Meanwhile , the detentions continue -- almost 1,800 a day . In addition to political party members , the crackdown has also swept up several journalists . `` That actually makes the arrests suspicious in some people 's minds , '' said Sultana Kamal , executive director of the legal aid group , Ain o Salish Kendro ( Law and Adjudication Center ) . `` If you just arrest any Tom , Dick and Harry saying this person may have arms , then people will legitimately raise questions about the mode of the whole operation . ''
The police have detained or arrested 18,000 people in three days . Human rights groups decry the actions as politically motivated . Round - ups continued after parties refused to cooperate with military government .