ANKARA, Turkey (CNN) -- Vice President Dick Cheney arrived Monday in Turkey to shore up relations with the key U.S. ally, which is facing protests from internal critics and complaints from neighboring Iraq.
Cheney touched down in the Turkish capital of Ankara hours after a Monday breakfast meeting with Israeli Prime Minister Ehud Olmert in Jerusalem.
He planned to meet with Turkish Prime Minister Recep Tayyip Erdogan and President Abdullah Gul.
Cheney's visit comes near the end of a weeklong trip through the Middle East, including an unannounced stop in Iraq, and Afghanistan.
Last month, Turkish troops launched an eight-day ground offensive into northern Iraq's Kurdish territories.
The rebel group, the Kurdistan Workers' Party, or PKK, has spent two decades fighting for autonomy for Kurds in southeastern Turkey.
The United States, European Union and Turkey consider the group a terrorist organization. But the Turkish attacks have raised concerns in Washington that military action could destabilize the U.S.-backed government in Baghdad.
The Iraqi government is not happy the PKK is using its territory as a base but views the Turkish military incursion as a violation of its sovereignty.
Another controversy brewing is a growing political struggle between Erdogan's ruling Justice and Development party and opponents who accuse it of undermining Turkey's secular society.
The weekend arrests of at least six intellectuals, including some critical of Erdogan's pro-Islamist government, have fueled tensions.
Among those picked up during a series of pre-dawn police raids Friday were newspaper editor and author Ilhan Selcuk, 83; Dogu Perincek, 66, the head of Turkey's Workers' Party; and Kemal Alemdaroglu, 69, the former head of Istanbul University, according to the men's attorneys.
Selcuk and Alemdaroglu have been released, while Perincek and three others were arrested and charged with helping a terrorist organization, Perincek's attorney said.
The three others are members of the media and Workers' Party, the lawyer said.
Selcuk's arrest followed a Friday column that compared Erdogan with the long-reigning French King Louis XIV, saying "Islamists -- moderate or radical -- believe they have taken over the country, provincial administrations, government and everything else."
Although predominantly Muslim, Turkey has retained a strong separation between mosque and state in line with the policies of Kemal Ataturk, the revered founder of the modern Turkish republic. Opponents have accused the Erdogan's party of moving the country toward an Islamic state.
The arrests sparked demonstrations over the weekend in Istanbul, Ankara and other Turkish cities. Protesters gathered in front of the offices of the Workers' Party and Cumhuriyet newpaper, where Selcuk is chief editor, demanding their release.
Culture Minister Ertugrul Gunay said the arrests are part of an investigation into the secularist "Ergenekon" movement. Government officials accuse the movement of plotting to overthrow the government, which won a new mandate in 2007.
More than 100 people were arrested last year as part of the probe. Oktay Eksi, head of the Turkish Press Council, said he fears the ongoing investigation could stifle journalism in his country. The council represents independent media organizations.
"The current atmosphere in Turkey leads one to believe that the investigation could turn into a new era of McCarthyism," Eksi said in a statement. "It is imperative, therefore, that world public opinion be informed of these developments marking Turkey's current-day political process."
The arrests came a week after Turkey's chief prosecutor, Abdurrahman Yalcinkaya, asked the country's constitutional court to consider shutting down the ruling party and banning 71 members -- including Erdogan, Gul and former parliament Speaker Bulent Arinc -- from public office. Yalcinkaya has issued previous warnings to the government over what he called anti-secular practices.
Last month, Turkey's parliament passed a constitutional amendment ending a ban on Islamic head scarves at universities, a move that sparked protests that drew tens of thousands to Ankara and Istanbul.
Critics have said the amendment threatens Turkey's existence as a secular state, and the measure remains under review by the country's constitutional court.
That court banned such scarves from universities in 1989, and it is still forbidden for women working in the public sector to cover their heads.
Erdogan's party, however, argued the university ban was an unfair denial of individual rights and religious liberty in a country in which two-thirds of women cover their heads. E-mail to a friend
CNN's Talia Kayali contributed to this report.