The ministry bomb attacks were among the worst in Iraq since 2003
Iraq has begun stationing thousands of extra police on its border with Syria to stop militants its says are crossing into Iraq to carry out bomb attacks.
Amid a growing row, the two countries have traded insults and recalled their ambassadors in recent weeks.
Baghdad says members of the Baath Party of former leader Saddam Hussein, hiding in Syria, organised two attacks in Iraq on 19 August which killed about 100.
Damascus has dismissed Iraq's claims as immoral and illogical.
Major-General Tariq Yusuf, police chief of Iraq's Anbar province, which borders Syria, told Reuters that Prime Minister Nouri Maliki had personally ordered the deployment.
"There is a government accusation against Syria relating to the bomb attacks. They have information that there is a threat from Syria," he told Reuters.
"We have caught two infiltrators trying to enter in the last two months."
Iraq is seeking the extradition of two suspects for the 19 August bombings, which targeted two government ministries in Baghdad.
But Syria has demanded to see proof that the two suspects are involved.
Iraqi Foreign Minister Hoshyar Zebari said: "We have given them the evidence that we have through the Turkish foreign minister and we are waiting for their response."
Baghdad has asked the United Nations to set up an international tribunal to try people from neighbouring countries suspected of orchestrating violence in Iraq.
During Saddam Hussein's 1979-2003 rule, Iraq and Syria were governed by rival branches of the Arab nationalist Baath Party and ties between them were characterised by mutual hostility.
Although diplomatic relations were restored in 2006, the overthrow of Saddam Hussein in 2003 saw many of his former allies flee to Syria, renewing tensions between the countries.