Sana’a, Reuters/Asharq Al-Awsat—Houthi fighters prevented Yemen’s new army chief from entering the defense ministry on Tuesday in a fresh show of power, a day after the Shi’ite faction accused the president of promoting corruption and demanded that it oversee state funds.

The escalation of tension between Houthis who control the Yemeni capital Sana’a and Western-backed President Abd Rabbuh Mansur Hadi raises the prospect of open confrontation after months in which Hadi sought to appease the group.

Houthi leader Abdul Malik Al-Houthi, in a speech to tribal leaders late on Monday at his northern Saada stronghold, said Hadi was a leading player in the country’s corruption.

“During the popular revolution and the popular escalation, President Abd Rabbuh Mansur Hadi was at the forefront of the forces of corruption,” he said, referring to anti-government protests led by the group before it captured the capital.

“The Yemeni people . . . will not be indifferent forever.”

A senior aide at the president’s office said the speech showed the Houthis, who have penetrated state institutions since seizing Sana’a in September, were plotting to bring down Hadi’s administration and “complete their takeover of the state.”

“We expect that the group has prepared another plot similar to the one it had when it captured Sana’a,” the official, who asked not to be identified, told Reuters.

Houthi said committees he had set up to oversee ministries since Sana’a’s fall had uncovered attempts by unidentified officials to conduct an inventory of state assets and to “divide billions” of rials among themselves in the process.

He also demanded that the 2015 state budget be subject to “close review” and that the government turn over control of state bodies to “rebels to monitor, follow up and ensure that people’s funds are not wasted.”

“Fighting corruption is a primary issue and there is no wavering from that,” he said.

Meanwhile, supporters of former president Ali Abdullah Saleh derailed a vote of confidence on the new government’s program in a parliamentary session on Tuesday, an official told the Associated Press.

Western powers have been worried about the volatile situation in Yemen, which shares a long border with oil giant Saudi Arabia, and which is also fighting Al-Qaeda militants and separatists in the south.

“Abdul Malik Al-Houthi’s speech points to an impending confrontation with the authorities. No one knows exactly where it may lead,” said Ali Saif, a Yemeni analyst.

Witnesses said Houthi fighters barred General Hussein Khairan, the army chief appointed by Hadi last week over Houthi objections, from entering his office.

Also on Tuesday, two car bombs exploded in Rada’ city in Yemen’s central province of Al-Bayda, killing at least 25 people, local and medical sources said.

The first car bomb exploded near a checkpoint manned by Shi’ite Houthi rebels while a school bus was passing, killing 15 students, sources said. The second car exploded near the house of an official in the area rumored to support Houthis killing ten, they said.

Rada’ is a bastion of the Yemen-based Al-Qaeda in the Arabian Peninsula (AQAP).The ascendance of the Houthis has angered AQAP, which views Shi’ites as heretics and Houthis as pawns of Iran.

The Houthis have friendly ties to Iran, the main Shi’ite power in the region and foe of Sunni Muslim Saudi Arabia. Their Shi’ite Zaydi sect is related to Iran’s dominant sect.