ISLAMABAD, Pakistan (CNN) -- A Pakistani television station, which has been critical of the government, has been shut down in locations across the country, according to the station's managing director.

Pakistani journalists at GEO-TV and political party activists protest in Karachi on Saturday.

Government officials have instructed cable operators to remove GEO-TV from the airwaves or push it farther down in the channel order, Azhar Abbas said Saturday.

The channel signal has been blocked in certain areas, but other cable operators are still carrying it. The channel is functioning and broadcasting in some areas in Pakistan.

The reported media shutdown comes as thousands of demonstrators and lawyers were headed to Islamabad for a four-day "Long March" to demand that the government immediately restore judges the previous president had ousted.

Demonstrators also plan a massive sit-in at the parliament building Monday.

After sweeping into power in parliamentary elections last year, Pakistan Peoples Party (PPP) promised to reinstate the judges within 30 days of taking office. The deadline came and went.

GEO-TV, which is known to have an anti-establishment stance, has criticized the PPP-led government in recent weeks. The station has aired numerous reports on the recent lawyers' movement.

The restrictions on local media has also led to the resignation of Pakistan's Information Minister Sherry Rehman, a high-ranking source in the Ministry of Information told CNN on Saturday.

Rehman handed in her resignation to Pakistani Prime Minister Syed Yusuf Raza Gilani, the source said.

Repeated phone calls from CNN to the Pakistani government for comment were not returned.

The renewed tensions threaten to take the focus away from the government's attempts to quash an escalating pro-Taliban insurgency in the country.

At the same time, Pakistan's economy is in chaos. The worsening security situation is part of the reason. Rising food and oil prices have also contributed to the crisis.

In November, the International Monetary Fund approved a $7.6 billion loan to Pakistan to help the South Asian country of 170 million people avoid an economic collapse.

Many in Pakistan worry that the latest turmoil could once again force the army on to the streets if it worsens.

In its 61-year history, Pakistan has been under army rule more than half the time. For now, Gen. Ashfaq Kayani has said he will not interfere in political matters.

CNN's Thomas Evans contributed to this report.

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