Turkey has warned of a cross-border offensive into northern Iraq, where an estimated 4,000 PKK members are based and from where the group is accused of staging attacks into Turkey.
The Justice and Development (AK) party government has said it backs the Turkish army, which has recommended the cross-border offensive, but has not reconvened parliament to approve the move.
Jaap de Hoop Scheffer, Nato's secretary general, called for restraint when he met Abdullah Gul, the Turkish foreign minister, on Tuesday.
"We openly declare that if the operations cease, the tensions will also cease"
De Hoop Scheffer said: "Nato cannot play a direct role there, but it shows its solidarity and is involved in the fight against terrorism. Nato hopes a solution can be found with a maximum of restraint."
Erdogan will chair an emergency security meeting with senior generals on Tuesday evening to discuss the toll from suspected PKK attacks across the border.
On Tuesday, the PKK offered a renewed ceasefire to the government if it agreed to end army operations against the group, a Kurdish news agency reported.
The separatist group has blamed the military for an increase in violence in the southeast of the country, but Tuesday's statement from the PKK said: "We openly declare that if the operations cease, the tensions will also cease.
"There has been a marked increase in [army] operations despite the fact that the unilateral ceasefire that our movement has been keeping since October 1 has not been formally abolished."
Ankara, which immediately rejected the October 1 truce, blames the PKK for the deaths of more than 30,000 people since the movement launched its armed campaign for autonomy in southeast Turkey in 1984.
In a statement, the PKK said attacks were the result of "self-defence and the use of our right of retaliation to losses".
Turkish military officials have said that between 3,500 and 3,800 PKK members are in northern Iraq and up to 2,000 in Turkey.
Turkey has deployed tens of thousands of soldiers along its border with Iraq and bombed suspected PKK positions inside Turkey.
Government forces have also set up temporary security zones in the southeast, effectively introducing emergency rule.