IRBIL, Iraq (AP) — U.S. Defense Secretary Ash Carter is meeting with Iraqi Kurdish leaders in their regional capital city of Irbil on Friday, to give him new insights into how the Kurds have managed to preserve an effective force in the face of Islamic State battlefield pressure.

Carter arrived on a military flight from Amman, Jordan, where he spent the night after holding meetings and giving a pep talk to U.S. troops in Baghdad on Thursday.

In Irbil, Carter is meeting with Masoud Barzani, president of the Kurdish regional government, and other Kurdish government and military officials.

The U.S. Is helping train and equip Kurdish armed forces, known as the peshmerga, in battles against Islamic State fighters.

The Kurdish forces, generally more experienced and more effective on the battlefield than their counterparts in the Iraqi army, have played a vital role in containing the Islamic State in northeastern Iraq.

They hold mostly defensive positions across large parts of northern Iraq and would be expected to play a key role in an eventual Iraq campaign to retake Mosul, which fell to IS in June 2014.

The U.S. military works closely with the Kurds, providing arms, training and advice. The Obama administration has resisted calls by some in Congress to bypass the Iraqi government in Baghdad and provide weapons directly to the Kurds. The administration instead has sent arms through the central government, reasoning that this preserves the hope of avoiding a final division of the country into sectarian and ethnic enclaves.

The Islamic State takeover of much of northern Iraq last year, including the city of Mosul, triggered a Kurdish push south and west to take control of the disputed city of Kirkuk, which is key to Iraq's northern oil fields.

After his Irbil visit Carter was returning to Washington, concluding a weeklong Mideast tour that started Sunday in Israel and included visits to Jiddah, Saudi Arabia, and Amman, Jordan.

It was Carter's first visit to Iraq since he took office in February.