Welsh Assembly members have failed to elect a new first minister on their return to the Senedd.
Labour's Carwyn Jones was expected to be re-appointed following Thursday's election.
But Plaid Cymru nominated its leader Leanne Wood, and won the backing of the Tories and UKIP, while Mr Jones won the support of sole Liberal Democrat Kirsty Williams and his own party.
With the vote tied at 29-29, the Senedd was adjourned to a later date.
Labour accused Plaid of doing a deal with the Conservatives and UKIP, something Plaid denied.
Despite losing one seat at the assembly election, Mr Jones had said he expected to form a minority Labour government with 29 of the assembly's 60 members.
On Friday, he spoke of having discussions with Plaid Cymru and Ms Williams to decide the way forward, but was not seeking any formal coalition.
Mr Jones remains first minister until assembly members vote to re-appoint or replace him.
'Don't force this'
Plaid AM Rhun ap Iorwerth said: "The people of Wales decided by a narrow margin in terms of the number of seats, but by a hefty margin in terms of the popular vote, that they didn't want Labour to have majority control in the National Assembly for Wales.
"We of course respected the right of Labour to have a first crack at forming a stable government, if you like, of seeking a majority.
"In a meeting this week Leanne Wood told Carwyn Jones to have a bit more time, don't force this vote today, have a bit more time in order to try to find a consensus, reflecting on the fact that they are in a minority.
"They decided not to take that opportunity. We put Leanne Wood's name up - why wouldn't we?"
Mr ap Iorwerth added that the assembly was "giving the signal... that this is an assembly without one party having a majority".
Welsh Conservative leader Andrew RT Davies said Labour had "no divine right" to assume Mr Jones would be elected first minister after its share of the vote fell.
"It is for new assembly members to explore, and discuss, the best way forward for the Welsh nation, which has for too long fallen behind the rest of the UK," he said.
"Certainly, I sense an appetite for a new kind of collaborative Welsh politics, and would welcome further discussions to build on those which led to today's vote."
A senior UKIP source, who was pleased with the result, said the party wanted "to dent the level of smugness within the Labour party".
Meanwhile UKIP group leader Neil Hamilton said the party was approached by Plaid Cymru on Monday to back Leanne Wood in the vote.
Reacting for Labour, Blaenau Gwent AM Alun Davies said: "I think Plaid Cymru have got to explain to the voters... why, less than a week after the election, they have now done a deal with the Conservative Party and with UKIP".
He said his party had a "clear mandate" to govern.
"People expected us to be given the right to form a government, and for the other parties to hold us to account on the way we perform in office," he said.
But Plaid's Mr ap Iorwerth said: "At no point did we offer anything, or consider offering anything, to UKIP or the Tories. They were simply informed of our intention to nominate Leanne as first minister."
Commenting on her decision to back Mr Jones, Lib Dem AM Kirsty Williams said: "I was not re-elected into the National Assembly to support a ragtag coalition made up of UKIP assembly members who at the moment can't even agree with each other.
"That is not my politics and not something I will even contemplate.
"I am disappointed that Plaid seem to think that is a viable option.
"The reality that we have to face is that Labour have 29 assembly members.
"It is therefore clear that they have the strongest mandate from the people of Wales."
AMs have 28 days following the election to decide on a first minister, which would mean a deadline of 2 June.
If there is no agreement, the UK government's Welsh Secretary Alun Cairns must call a fresh election.
Earlier on Wednesday, Plaid Cymru AM Elin Jones was elected as the new presiding officer, defeating party colleague Lord Elis-Thomas.
Analysis by Nick Servini, BBC Wales political editor
This is about Plaid Cymru flexing its muscles and sending out a signal, following the accusations that Labour had had it easy in the previous five years in the assembly.
Labour says it is a stunt, with Plaid Cymru doing deals with the Conservatives and UKIP.
Plaid's riposte is that Labour has been arrogant in the run up to Wednesday's events, with Carwyn Jones offering nothing clear on his plans for government.
Labour AMs have been walking around with faces like thunder and, although one Plaid Cymru AM has said it was not about giving them "a bloody nose", it has created bad blood.