Israeli police have extended the scope of their investigation into allegations of corruption against Prime Minister Benjamin Netanyahu.

The police are examining two new issues related to graft charges against Netanyahu, including his alleged role in the purchasing of Dolphine submarines from Germany and another issue which has not been disclosed yet, Channel 10 television reported on Monday.

Netanyahu's cousin, family lawyer and confidant, David Shimron, has reportedly been involved in the deal to purchase the submarines from Germany's ThyssenKrupp company.

Netanyahu is currently under investigation for several separate charges of corruption and has been grilled by police twice in recent weeks. The investigation has come as a shock to Israel’s political scene, prompting speculations about Netanyahu’s resignation.

Netanyahu, however, has denied the allegations and accused Israeli media of “pursuing an unprecedented campaign against me in order to bring down Likud government.”

Israeli protesters shout slogans during a rally against Israeli Prime Minister Benjamin Netanyahu and his policies in Tel Aviv on January 14, 2017.

On January 14, protesters gathered on the streets of Tel Aviv, calling for the resignation of Netanyahu over growing allegations of corruption.

One part of the investigation involves him allegedly proposing commercial favors to an Israeli newspaper owner in return for positive coverage.

Last week, a recording emerged of Netanyahu offering the owner of the Yedioth Ahronoth newspaper a reduction in the circulation of the pro-Netanyahu newspaper, Israel Hayom, if Arnon Mozes’ paper took a more favorable stance towards him. A drop in the circulation of Hayom would be a direct benefit to Mozes as it is his main rival in advertising revenues.

Another investigation is related to charges of receiving illegal donations and gifts amounting to around some $100,000 in cigars and alcoholic beverages.

He is also under investigation over suspicions that he accepted one million euros (about 1.1 million dollars) from French fraudster, Arnaud Mimran, for campaign funds during the 2009 Israeli elections.

The Netanyahu family has faced scrutiny over accusations that their lifestyle is out of touch with regular Israelis. Netanyahu’s wife, Sara, has also come under fire for her lavish tastes and abusive behavior toward members of her housekeeping staff.