NATO Secretary General Jens Stoltenberg and US Secretary of Defense James Mattis arrived in Kabul early Wednesday on an unannounced visit and met with General John Nicholson, US commander in Afghanistan.

Mattis and Stoltenberg are also expected to meet Afghan officials while in the country. No details have been given as to the length of their stay.

This is the first trip by both officials after US President Donald Trump announced his new war strategy for Afghanistan and south Asia.

On Tuesday, Mattis met India’s Defense Minister Nirmala Sitharaman and discussed the issue of terrorist safe havens in Pakistan.

According to the Times of India, both parties agreed that such sanctuaries should not be tolerated.

In the meantime, Sitharaman told Mattis that New Delhi will continue to assist Afghanistan but it will not get involved militarily.

Sitharaman also said she made India's stance on Afghanistan clear to Mattis, by emphasising it won't contribute troops but will continue developmental assistance.

"I borrowed the defense secretary's own (earlier) words when I explained to him that the very same forces that find safe haven in Pakistan have been the ones who've affected New York as well as other places," said Sitharaman, after meeting with Mattis.

The Times of India also reported that Sitharaman asked Mattis to raise the issue of cross-border terrorism and terror safe havens if he visits Pakistan.

India's ANI news agency meanwhile reported that Mattis said: “Our two countries recognise the threat that global terrorism poses to people throughout the world.”

Mattis' trip to India comes two months after US President Donald Trump said that India must play a bigger role in Afghanistan's path to peace.

On Tuesday, Mattis acknowledged that India has already contributed significantly to this process.