Poland and the Baltic countries have accused the Belarusian government of pushing migrants, most of them from the Middle East, across their borders in an effort to destabilise both its neighbours and the EU.
"In line with an earlier announcement, the president signed a motion to the Sejm today for its approval to prolong the state of emergency by 60 days," the head of Poland's National Security Bureau (BBN), Pawel Soloch, said on Wednesday.
He added that the motion will be presented to MPs and put to a vote on Thursday.
On Tuesday, the Polish government decided to ask the president to prolong the state of emergency, introduced for 30 days on September 2 and covering a three-kilometre deep strip adjacent to the Belarusian border, for an additional 60 days.
The president met with the ministers of interior and defence and the head of the Border Guard to hear a situation report on the same day.
Soloch said that by submitting the motion, Duda endorsed the arguments of the government on the need to extend the state of emergency.
"We are dealing with a persistent threat to citizens and public order in the border areas," Soloch said.
According to him, recent data allow one to talk about "an escalation of migratory pressure on the border" aggravated by "the dangerous, provocative behaviour of the Belarusian security services towards Polish soldiers and (border) officers."
Soloch said that in the BBN's assessment there is a risk of a long-term deterioration in the security situation along the entire EU border with Belarus, including in Lithuania and Latvia.
In his opinion, this is related to the increasing dependence of the Belarusian authorities on Russia.
"This is a new reality against which both border states and the community will be forced to find an answer," Soloch said.
According to the government on Monday, there have been 9,400 attempts to illegally cross the Polish border from Belarus since August 8, 200 of which were foiled.
The government also claims that some of the migrants have links to terrorist or paramilitary groups, including the so-called Islamic State, while others had unspecified Russian connections.
Under the state of emergency the press is banned from entering the areas it covers. (PAP)