A walk-out at Pakistan's leading telecoms company, which has severely hit communications throughout the country, has entered its fifth day.
Workers shout anti-government slogans in Karachi
Talks between unions and management have failed to reach a breakthrough as workers protest against the planned privatisation of the state-run company.
They fear this could lead to mass job losses at Pakistan Telecommunication Company (PTCL).
Commentators believe the government may intervene to try to end the strike.
Unions claim that 55,000 employees are on strike, while the company says a skeleton operation is running with 6,000 workers.
Local papers reported that several hundred police and Frontier Constabulary (FC) were being mobilised to flush out striking workers from PTCL headquarters in Islamabad, should talks between unions and management break down.
Information and technology minister Awais Leghari told a local TV channel that the government planned to deal with striking workers severely, describing them as "miscreants".
PTCL is the most profitable public utility in Pakistan and is a critical part of the government's privatisation policy.
The government holds an 88% stake in PTCL and plans to offload a 26% controlling stake in the firm, in what would be the largest business sell-off in Pakistan to date.
A barrage of international telecom peers - including Singapore Telecoms, China Mobile HK, Telekom Malaysia, Saudi Oger, Emirates Telecoms, Turkcell and the Almal Consortium of Egypt - have been shortlisted as potential buyers.
So far, the strike has slowed down repair and maintenance of some of the company's more than five million fixed phone lines.
"If the government sticks to its privatisation plans, we'll shut down all the company's operations," said Zia Uddin, who is leading an alliance of nine different trade unions representing PTCL workers.
Workers are also concerned that the firm is being sold off too cheaply.
"It should have been double what the government is demanding," said Zia-ud-Din, president of PTCL Employees Union.
The controlling stake PTCL is being sold for is $2.5bn ($1.37bn), while unions believe it could easily fetch over $5bn.
Meanwhile, PTCL is confident that a deal to end the strike action will be reached soon, despite the fact that the two opposing sides remain split on the privatisation plans.
"They have some apprehensions on job security in a post-privatisation scenario," said executive vice president Ali Qadir Gilani.
"The government is trying to address those apprehensions, but the anti-privatisation demand is totally unjust."
If a deal with the workers fails to materialise the army is on stand by to keep the country's telecoms network operating.
The nine unions are meeting on 5 June to decide upon their next course of action.
The bidding for the 26% stake in PTCL begins on 10 June and a deal is expected to be completed by the end of June.