Poland's parliament has met for the first time since last month's crucial general election.
Speaking to the country's 460 elected deputies, Polish President Andrzej Duda said that he will be "the guardian of the greatest achievements of the last eight years".
Mr Duda is widely viewed as an ally of the nationalist-populist Law and Justice party, which has governed Poland since 2015.
He also said that he would "not hesitate" to use his veto, which, he added, he had previously used when legislation was proposed by his own "political camp", meaning Law and Justice.
Yesterday evening, Mr Duda formally appointed Mateusz Morawiecki as Prime Minister, as a representative of the Law and Justice.
Mr Morawiecki and Law and Justice now have 14 days to win a vote of confidence and form a government.
A pro-EU coalition of centrist and left-wing parties, led by former Prime Minister Donald Tusk, won a majority of seats in parliament and will vote against Mr Morawiecki's nomination.
The coalition will then propose Mr Tusk as its candidate for prime minister, likely to be in early December.
"I don't think we've ever had a presidential speech at the opening session of parliament that was as partisan," Adam Jasser, a former head of policy in Mr Tusk's previous government a decade ago, said.
Law and Justice won 194 seats, the largest of any party, but lost its parliamentary majority in the election on 15 October.
A date for the vote on Mr Morawiecki's nomination for prime minister, who resigned his current position as a formality, is yet to be set but must happen within the next 14 days.
A government led by Mr Tusk would seek to repair relations with EU institutions, which have soured mostly due to changes made by two successive Law and Justice governments to the judiciary.
The EU claims that the independence of judges and courts have been reduced and, as a result, has frozen €35 billion in post-pandemic recovery funds.
It has also blocked the transfer of €76 billion in EU cohesion funds set aside for Poland.
Mr Tusk has said that unblocking frozen EU funds is one of his key priorities.

In a first display of the coalition's parliamentary majority, Szymon Holownia, the leader of Poland 2050, which campaigned in the election as part of the centre-right Third Way, was elected as the Marshal, or Speaker, of the lower house.
Mr Holownia's nomination received 265 votes, defeating the Law and Justice candidate Elzbieta Witek, who received 193 votes.
MPs from the far-right Confederation backed Mr Holownia's candidacy, a clear indication that the party will not align itself with Law and Justice.
Mr Tusk said on X, formerly Twitter, that he dedicated the result of vote to President Duda, hinting that the opposition bloc held the balance of power in parliament.
For more than a decade, Mr Holownia was the host of the television programme, Poland’s Got Talent.
He is a first-time MP and a devout Catholic.
The coalition parties share similar positions on security, transitioning to greener energy sources and raising the wages of public sector workers.
However, abortion legislation is a sticking point among the bloc.
Both Mr Tusk’s centrist Civic Coalition and the Left, an alliance of smaller left wing parties, support the liberalisation of Poland’s current restrictive abortion laws, and want to allow abortion up to the 12th week of pregnancy.
Mr Holownia indicated during the election that he would favour a referendum on the issue.
His centre-right Poland 2050 party is likely to give its MPs a free vote on any proposed bill to amend current abortion legislation.
However, deputies from the socially conservative PSL, a farmer’s party which makes up half of the Third Way coalition, are more likely to shun liberal abortion legislation.
"The abortion issue is also going to be important because, for a lot of young people and women voters, they really want this to be delivered," said Mr Jasser, deputy managing editor of Visegrad Insight.
Reuters reported on Saturday that the coalition parties had reached an agreement in favour of overturning the Constitutional Tribunal’s ruling from October 2020 that introduced a near-total ban on abortion.
Speaking to parliament yesterday, Mr Morawiecki outlined, what he defined as, the achievements of the outgoing Law and Justice government: supporting Ukraine, continued economic growth and his party's opposition to "illegal immigration".
The opposition coalition's candidate for Speaker of the Senate, Poland's upper house, was also approved by a majority vote.