Ahead of President Donald Trump’s visit to Israel, the head of a leading Christian Zionist organization called on the president to fulfill his election campaign promise to move the U.S. embassy from Tel Aviv to Jerusalem. At the same time, several prominent U.S. senators have introduced a resolution which would effect the move immediately.

Pastor John Hagee, head of Christians United for Israel (CUFI), noted in a letter published on Monday in the Washington Times that Trump will soon need to decide whether to postpone the embassy’s transfer to Jerusalem by at least half a year.

In 1995, Congress passed the Jerusalem Embassy Act, which calls on the U.S. to move the embassy to Jerusalem and recognize the city as Israel’s capital. But every sitting president since then has opted to sign successive six-month waivers delaying the move. Most recently, former President Barack Obama signed the waiver in December. Trump has a June 1 deadline to choose between another waiver or an embassy move.

“Throughout his campaign, Mr. Trump promised to move the embassy. This promise was vital to securing the support of millions of Christian Zionists around the country,” Hagee wrote.

“Like [former President Harry] Truman, Mr. Trump must contend with well-entrenched anti-Israel bureaucrats at the State Department who will try to use their positions to make moving the embassy difficult. But the buck does not stop with bureaucrats,” he wrote.

Hagee added, “The Jewish state has the right to determine where it would place its capital, and it has chosen Jerusalem. The international community’s decision to cower before Israel’s enemies by keeping embassies in Tel Aviv is disgraceful.”

On Wednesday, U.S. Senators Dean Heller (R-NV), Lindsey Graham (R-SC), Ted Cruz (R-TX), and Marco Rubio (R-FL) introduced a resolution to urge the recognition of Jerusalem as the capital of Israel and the relocation of the U.S. embassy from Tel Aviv to Jerusalem.‎ In January, Heller introduced the Jerusalem Embassy and Recognition Act, legislation that would do just that by forcing the U.S. Department of State to fulfill its promise to relocate the U.S. embassy to Jerusalem or face a penalty.

In order to encourage the implementation of the law, Heller’s resolution expresses the sense of the Senate that the U.S. Embassy should be moved to Jerusalem.

“It’s been more than 20 years since legislation to move the U.S. Embassy from Tel Aviv to Jerusalem became law, yet we have still not fulfilled our commitment to Israel to do so,” said Heller. “Our resolution encourages the Administration to act on our decades old promise and finally move the U.S. Embassy to Jerusalem. It also sends a message to our strongest and oldest ally in the Middle East: the United States Senate stands with Israel.”

With additional reporting by Breaking Israel News staff