The leader of Italy's far-right League party, Matteo Salvini on Monday claimed he was "proud" to be doing everything possible keep his electoral pledges and "to give Italy and our children a brighter future".
"I am proud to be doing my level best to keep our promises and to give Italy and our children a brighter future," Salvini tweeted.
"Thanks my friends, I love you," the tweet continued.
Earlier on Monday, Salvini and populist Five-Star Movement party leader Luigi Di Maio said they had agreed a programme for a coalition government in overnight talks - allegedly including its prime minister.
The programme of government reportedly agreed by the Five-Star and the League includes lowering the retirement age and tax cuts.
If Mattarella approves Di Maio and Salvini's pick of premier, lawmakers could vote confidence in the proposed cabinet later this week. Mattarella gave the parties until Sunday to agree on a tie-up and was on Monday meeting Di Maio and Salvini separately.
Italy has been in political limbo since the inconclusive 4 March national election in which populist parties made strong gains.
Five-Star is the biggest political party and the centre-right is the largest bloc in the hung parliament. Several previous rounds of talks with Italy's political leaders collapsed amid a mesh of seemingly irreconcilable demands.
If the Five-Star-League tie-up falls through, Mattarella will appoint a caretaker government to oversee a re-vote in the coming months.
